History Main / MusicalWorldHypotheses

* The stage version of ''Theatre/{{Cabaret}}'' includes a lot of diegetic songs, performances at the Kit Kat Klub, but also a high percentage of songs like "So What" or "It Couldn't Please Me More", which fall under the Alternate Universe distinction.

* Flavor 2, '''The All In Their Heads Hypothesis''': There is no singing; the songs are an artistic rendering of the characters' fantasies, with the format of song in a way serving to distinguish between what really happens and what is only in the characters' heads, much like a [[Creator/WilliamShakespeare Shakespearean]] [[ThinkingOutLoud soliloquy.]] Naturally, this means that no characters are aware of what goes on in another character's song: there may be duets, but then they are {{Distant|Duet}} {{Counterpoint Duet}}s where the two characters do not know of one another's participation. This makes the musical more palatable for some, since there is obviously no literal singing involved in-universe. TiredAfterTheSong contradicts this because there's no way you can tire yourself out by imagining singing.

* ''ComicBook/ScottPilgrim'' is a strange case. The comics have it as a straight AU example, and is the ''least'' weird thing about the universe (which includes universities in the sky, glowing heads, power-ups, 1-ups, magical/vegan powers). The film, on the other hand, treats Matthew Patel bursting into song as very strange even for the universe (as evidenced by Stacey's "what the fuck?" expression)

* ''Fanfic/LightOfTheMoon'': When Rapunzel sings to herself about leaving the tower for the first time, Flynn seems confused as to why she's singing. Varian simply comments that she does it a lot.

* When ''WesternAnimation/{{Daria}}'''s MusicalEpisode first came out, there was a rash of fanfics explaining it away as [[AllJustADream a dream]]. Some fans take the Adaptational approach, arguing that the main events of the episode (a hurricane hits the town, Daria and Jane are trapped with Kevin and Brittany, etc.) could have happened if you ignore the singing. [[https://www.fanfiction.net/s/7714460/33/Not-So-Different This fanfic]], retelling the whole series, did this episode in [[EpistolaryNovel diary entries]] to make it ambiguous.
* ''Fanfic/TheDragonAndTheButterfly'' goes with the "all in their heads" interpretation, due to most scenes being shown from Hiccup's POV. "Pressure" is just Hiccup watching Mirabel and Luisa having a long and heartfelt talk, while "What Else Can I Do" is him minding his own business in the smithy when, without warning, Isabela unleashes the plantocalypse on the town. It's in fact played for a good measure of horror - with a child being trapped in a house by vines, among other things - as the townspeople clearly can't deal with the sudden horticultural assault. The song "We Don't Talk About Bruno" is instead "We Don't Talk About Hiccup", but instead of being sung it's the Viking teens and Berkian townspeople explaining why Hiccup was viewed as a disgrace (with the narrative stating that it's "almost like they're singing"). "Welcome to the Family Madrigal" gets the same treatment, with the song instead being Hiccup telling the Madrigal family history (but with reworked lyrics to reflect how the family has changed since the events of Encanto).

*** "Reindeer(s) Are Better than People", however, is clearly diegetic, as Anna explicitly comments on the song after it is done and the way it is presented implies that Kristoff sings this every night. Meanwhile, it's unknown how "Frozen Heart" fits, but it most likely fits as diegetic, as the singers are clearly sawing to the beat of the music and, as demonstrated by ''Snow White and the Seven Dwarfs'', it's perfectly normal to sing while working. ''WesternAnimation/FrozenII'' reveals that the iconic "Let It Go" is diegetic too. While it at first seems to be All in Elsa's Head because she's all by herself at the time, meaning that it's probably an inner monologue, the sequel has a scene of her [[OldShame cringing]] at a flashback of herself singing that song, meaning that she ''did'' sing it in real time and come up with the lyrics on the fly.

* ''Film/Annie1982'': The "Betcha" song is definitely Alternate Universe, since Miss Hannigan asks, "Do I hear singing in here?". The rest are unknown.

* The ''Series/FlightOfTheConchords'' TV show is about musicians, and thus a lot of the songs are diegetic (e.g. ''Bret, You've Got It Going On'', ''If You're Into It'' and ''Albi the Racist Dragon'', the last being on a ShowWithinAShow). However, other songs are All In Their Heads (e.g. ''She's So Hot, Boom'', which stylistically shows the girl it is sung to during it but is still obviously not actually being performed for her, ''Business Time'', ''Mermaids'', ''Sugarlumps''), and others are clearly Adaptation Hypothesis examples (e.g. ''Most Beautiful Girl in the Room'', ''Hurt Feelings'', ''I Told You I was Freekie'').
** In the Flight of the Conchords song ''Hiphopopotamus vs. Rhymenoceros (feat. the Hiphopopotamus and the Rhymenoceros)'', which is All in Their Heads, one of the muggers asks if they 'were dancing a little bit just then'. They say no, sheepishly.
* [[DeconstructedTrope Deconstructed]] in the MusicalEpisode of ''Series/{{Scrubs}}'', "My Musical," as the singing was a hallucination of a patient who had a stroke, and in fact her life was in danger. When she is cured, it stops, but the episode ends with her humming to herself as she misses the music inside her head. So All In ''One'' Character's Head, mixed with the spirit of the Adaptation Hypothesis (characters singing to each other are really having those conversations, but not really singing).
** This also causes a bit of FridgeBrilliance to kick in, since the patient isn't around for any of the actual dialogue sequences, and as soon as she does appear, characters break into song, even if they're halfway through a conversation.

* Norm Macdonald {{Lampshaded}} this a couple of times on ''[[Series/SaturdayNightLive SNL]]'', once in [[http://snltranscripts.jt.org/96/96oevita.phtml "Evita"]] and once in a [[http://www.fakenews.net/archive/bit_parts/west_side_story_96_11_16.html "West Side Story" Expy]].
-->'''Eva Peron''': ''Don't cry for me, Argentina,''
---->''The truth is I never left you''\\
''All through my wild days''\\
''My mad existence''\\
''I kept my promise''\\
''Don't keep your distance.''
-->'''Juan Peron''': What the hell was that?\\
'''Eva Peron''': What was what?\\
'''Juan Peron''': You were singing.\\
'''Eva Peron''': Oh.. I, I, I did, didn't I?\\
'''Juan Peron''': Yeah, yeah, don't do that!
* One of Alex Borstein's characters on ''Series/MadTV1995'' was a redhead named Theatre/{{Annie}} whose spontaneous musical outbursts were stated to be a stress-triggered mental illness.
* ''Series/{{Glee}}'' seems to primarily be diegetic, but mixes in a decent sprinkle of "All in Their Heads", numbers. Also, it doesn't do to think too hard about the quality of some of the first read-throughs from a purely diegetic perspective.
* ''Series/EvenStevens''' "Influenza: The Musical" is a combination of Alternate Universe and All In Their Head. Specifically, [[AllJustADream Ren's]].
* ''Series/ThatsSoRaven'' had a diegetic musical episode, wherein all the wacky antics are supposed to wow a talent scout disguised as a janitor.

* The musical episode of ''Series/{{Sanctuary}}'' is an interesting variation. Abby is singing (without realizing it) to other characters because she's been infected with a parasite that interferes with processing and producing normal speech. Everyone else sings to Abby out of necessity since she can't understand them otherwise. The songs are not rehearsed and are basically just sung dialogue.
* One ''Series/SaturdayNightLive'' skit, Creator/ZacEfron plays his signature character, the star of the ''Film/HighSchoolMusical'' series, giving a speech to his former classmates after he'd spent a year at college. He crushes their illusions (and lack of MediumAwareness) by explaining that the music seems to stop after graduation, and spontaneous singing just gets you funny looks. (So it's the alternate universe interpretation combined with LikeRealityUnlessNoted.)
--> "And from what I can tell, this is America’s ''only singing high school!'' I was as shocked as you are."

* The first half of ''Series/MadMen'''s last season ends with Bert Cooper performing "[[Music/TheInkSpots The Best Things in Life Are Free]]" for Don with several unknown women. Considering all the performers disappeared the second it ended, no one reacted to it except Don, and [[spoiler:Cooper had just ''died'' earlier than day]], this falls pretty clearly in "All In Their Head".
* ''Series/CrazyExGirlfriend'' can vary from song to song, but the number of quickly reversed changes in setting and costume, the out-of-nowhere [[SummonBackupDancers backup dancers]], and the switches to animation or DeliberatelyMonochrome footage and back point to "All In Their Heads." This is also implied by a number of lines indicating Rebecca likes to imagine herself as a theatre heroine living her life in glorious song, and some numbers make it obvious - in "Ping Pong Girl", she's clearly fantasising about how she wants Josh to react, and we constantly cut back to her nodding and smiling at the daydream. Audio commentary also notes that when a character other than Rebecca gets in on the singing, that's a sign that they've been brought into her madness.
** The series finale outright states that it's all in Rebecca's head. [[spoiler:Paula sees Rebecca staring vacantly into space again and finally asks her what she experiences whenever that happens. Rebecca somehow brings Paula into her musical mind-space, and Paula, blown away by how creative it is, convinces Rebecca that she should pursue songwriting as a way to share all of that creativity with others.]]

* ''Series/{{Psych}}: The Musical'' is explicitly an Adaptation -- the last scene reveals that the musical the audience just saw was an artistic rendering of a musical Shawn wrote, adapted from an actual case the characters worked on. It's safe to assume there was really no singing involved when, say, Woody actually explained his finding of suicide rather than murder, Jules and Lassiter actually discussed the case in the chief's office, or one of the criminals actually died.

* ''Series/SesameStreet'':
** "Cry", sung by a baby, could be All in His Head, since he sings, "I wish I could speak", which would be odd if he really were singing. On the other hand, the character Baby Music/FatsDomino is explicitly a singer, meaning he's a BrainyBaby and his songs are Diegetic.
** "Goodnight, Natasha" is Diegetic, since it's a lullaby sung by Humphrey to Natasha. Conversely, "Wake Up" is a song meant to wake you up, and since Gina sings it to the daycare students, it's probably Diegetic too.
** Most of Ernie's songs are Alternate Universe-- Bert clearly knows that Ernie is singing, and is usually annoyed by it.
** "Share" is Alternate Universe, since one spoken line is "What do you think we've been ''singing'' about?", revealing that they really were singing.
** "That's Being a Cat" is Diegetic-- it's a song sung for TV by a TV star.
** "The Monster in the Mirror" is an Adaptation, since Grover is singing about something that happened in the past. However, he states that the "wubba wubba wubba" part was said in song, so it's an adaptation of a time which actually involved singing.
** "What's the Name of That Song?" is a tough one. In-universe, the characters are trying to identify a separate song, and so are singing some of the lyrics they do remember (la de da de dum mostly). However, it's unclear if the rest of the lyrics are being sung or spoken in-universe. One rendition of the song involved a FourthWall gag where someone asks the question in the title and [[WhosOnFirst the other thinks they were speaking of the actual song]], meaning that it was literally being sung in that instance. However, for other renditions, it's still unclear. Someone (usually Oscar) says, "They keep on singing that song" but he could be referring to them singing the lyrics they know to try to identify it.
** The asthma rap Danny sings is Diegetic. He's explicitly saying that he's rapping to explain his asthma.
** "Accidents Happen" is Alternate Universe, since Grover says, "Song cue" before it begins.
** "It's Christmas Again" is Diegetic, since it's a Christmas carol the singers wrote and they lose their voices from singing it too much.
** "The Crying Game Song" is also Diegetic, in that it's a song Elmo made up to advertise his game.
* ''Series/WorzelGummidge'': The song about "put a 'wor' after 'w',", etc, is Diegetic-- it's a song that he made up in order to teach Worzelese, his special language/code.
* ''Series/ZoeysExtraordinaryPlaylist'' features a twist on All In Their Heads; Zoey’s abilities as TheEmpath are filtered through random musical numbers that only she can see and hear, with the song choice reflecting the performers’ thoughts and feelings. However, some numbers also take place diegetically, like Mo's choral performance and Max's flashmob.

* ''Series/HighSchoolMusicalTheMusicalTheSeries'' is almost entirely Diegetic in the first season: every musical number is either a rehearsal or performance connected to the characters' involvement with the titual school play or their own songwriting exploits, and the one exception is AllJustADream. The second season blurs the line somewhat: while there are still plenty of performances happening in universe, a few are All In Their Heads.
* ''Series/Lucifer2016'' occasionally has one-off musical numbers that are clearly Diegetic and the result of characters, usually Lucifer, putting on a performance for story reasons. The season 5 MusicalEpisode [[Recap/Lucifer2016S05E10BloodyCelestialKaraokeJam "Bloody Celestial Karaoke Jam"]] includes random crowd numbers [[AWizardDidIt with the explanation that]] {{God}}'s presence on Earth is causing humans to act strangely and break into songs that they forget once the number is over.

* ''Series/TheAfterparty'''s MusicalEpisode is a case of Adaptation, given that the show is a RashomonStyle GenreRoulette and this particular episode is from the perspective of wannabe musician Yasper.
* ''Series/StarTrekStrangeNewWorlds'' has this happen in [[Recap/StarTrekStrangeNewWorldsS2E09SubspaceRhapsody Subspace Rhapsody]], with the Alternate World variant; after an experiment with a subspace fold transmits music into it, it creates a quantum uncertainty field where the crew of the ''Enterprise'' literally enter an alternate reality where people sing uncontrollably in response to strong emotions. It is mentioned the effect extends across the Federation and half the Klingon Empire, but the only singing from outside the ''Enterprise'' to be shown is a communication with another Starfleet ship that turns into both captains singing, and a quick scene of a Klingon bridge crew [[spoiler: singing in K-pop style]].

* ''VideoGame/BrutalLegend'' is explicitly a Musical Alternate Reality. [[MagicMusic Musical performances are analogous to spells,]] from practice chords conjuring fireballs and lightning bolts, to three-bar solos that cause, for example, kickass hotrods to be conjured to zeppelins to crash into things. Performing a concert is to impose your will on Reality itself, with the style of music being played expressing a faction's worldview. Heroic Ironheade plays epic music that embodies freedom, the villainous, [[TheLegionsOfHell outright demonic]] Tainted Coil plays [[ObligatoryBondageSong seedy]] music that embodies authoritarianism, and the [[EvilVsOblivion nihilistic]] Drowning Doom plays spooky power metal that speaks of a desire to [[MilesToGoBeforeISleep lay down and die, but not before]] [[SuicidalCosmicTemperTantrum they help everyone else die first]].

* ''WebVideo/AbridgedOnTitan'' is largely Diagetic. Armin improvises ''Please Don't Kill Us, Please'' on the spot, and Dot Pixis pardons him explicitly because he liked the song; Eren later repeats the song and gets Levi to want him on his squad because his voice is a good fit for Levi Squad's quartet ''Levi's Lovelies''. The song that Levi Squad sings was rehearsed beforehand, and [[spoiler: was part of Levi's plan to alert the rest of the group about when to spring the trap on the Female Titan]]. ''F**k It'' dips into Alternate Universe and All in Their Heads, as the first verse (sung by Annie when she's revealed as the Female Titan) gets a surprised reaction from Eren, and the rest of the song is Annie and Eren's internal monologue as they're having a vicious fight in Titan form. InUniverse, the term for spontaneously bursting into song as a tactic is called the Menken Musical Maneuver. While it apparently was a horrible failure for Dot Pixis, it's worked surprisingly well each time it's tried in the present.

* [[https://www.youtube.com/watch?v=ohIisKwUvsY Love Is Like Drugs]] uses the Alternate Universe Hypothesis, as shown by WebVideo/{{Jontron}}'s song lines triggering his curse and affecting the plot. It's implied but not stated that Jontron's curse is the cause of the background music.
* There's a music number about it in ''WebVideo/LoadingReadyRun'' appropriately named "[[WillingSuspensionOfDisbelief Suspend Your Disbelief]]".[[http://loadingreadyrun.com/videos/view/86/Suspend-your-Disbelief]]
* Discussed in ''Website/{{Cracked}}'''s [[http://www.cracked.com/blog/5-videos-that-will-brighten-your-day/ 5 Videos That Will Brighten Your Day]]. It describes the video "[[https://www.youtube.com/watch?v=gOfOIQ5ayzI College of DuPage Flash Mob Dance and Pep Rally]]", in which a FlashMob of a half dozen people perform rehearsed dance moves, and then someone outside the group spontaneously joins in the dance fever. The author jokes that the outsider is attempting to fit into an Alternate Universe: "Oh, life is a musical now? OK, I'd better adapt!"
** Also discussed in the video [[http://www.cracked.com/video_18577_the-horrifying-truth-about-life-inside-movie-musicals.html "The Horrifying Truth About Life Inside Movie Musicals"]], where they suggest telepathy, puppeteers, slavery, fascism, mental illness, and the idea of singing and dancing providing a drug-like high as in-universe reasons why everybody sings in musicals.
* In ''WebAnimation/IfTheEmperorHadATextToSpeechDevice'' Episode 28, the Captain-General of the Custodes and his entourage have a debate with the Fabricator-General of Mars in binary, which is presented in English as a song, implying the adaptation hypothesis. The Man-Emperor of Mankind, who was watching via holovid (and has a history of displaying MediumAwareness), also discusses the trope by saying "I cannot tell if that was diegetic or not."
* ''WebVideo/JennyNicholson'' discusses this in the context of ''Film/DearEvanHansen'', noting a number of decisions (some [[AdaptedOut adaptational]], some in framing) weaken suspension of disbelief and muddy the rules of the musical world. She highlights a song that gives the impression it, but no other, is really happening, and a character has inexplicably decided to ''sing'' his confession as the people listening stare at him with confusion and revulsion, occasionally interjecting with spoken dialogue.

* In ''WesternAnimation/HazbinHotel'' It’s implied that Lilith, and by extension Charlie, have the power to turn the world around them into a type 1. We see Charlie apparently have some reality warper powers during her song in the pilot that were picked up by the cameras. The StorybookOpening for the first official episode said Lilith empowered demon kind with her voice and passed on her dream on to her daughter. This is apparently why the people of Pentagram City regularly break into musical numbers while stories told in parts of the Helluverse that are outside Charlie’s vicinity have songs as part of [[DisneyAcidSequence drug trips,]] [[LeftTheBackgroundMusicOn played on the radio,]] or sung by performers on stage.

* In ''WesternAnimation/HazbinHotel'' It’s implied that Lilith, and by extension Charlie, have the power to turn the world around them into a type 1. We see Charlie apparently have some reality warper powers during her song in the pilot that were picked up by the cameras. The StorybookOpening for the first official episode said Lilith empowered demon kind with her voice and passed on her dream on to her daughter. This is apparently why the people of Pentagram City regularly break into musical numbers while stories told in parts of the Helluverse that are outside Charlie’s vicinity have songs as part of [[DisneyAcidSequence drug trips,]] [[LeftTheBackground!usicOn played on the radio,]] or sung by performers on stage.

* In ''WesternAnimation/HazbinHotel'' It’s implied that Lilith, and by extension Charlie, have the power to turn the world around them into a type 1. We see Charlie apparently have some reality warper powers during her song in the pilot that were picked up by the cameras. The StorybookOpening for the first official episode said Lilith empowered demon kind with her voice and passed on her legacy to her daughter. This is apparently why the people of Pentagram City regularly break into musical numbers while stories told in parts of the Helluverse that are outside Charlie’s vicinity have songs as part of [[DisneyAcidSequence drug trips,]] played on the radio, or sung by performers on stage.

* ''WesternAnimation/HazbinHotel'' mostly features diegetic songs, with characters commenting on other people singing, but occasionally delves into the other variants. For example, the scenery in Vox's half of "Stayed Gone" shows either a TimeCompressionMontage or very fast set changes.

* ''WesternAnimation/AdventureTime'' occasionally uses Diegetic, while also putting a SurprisinglyRealisticOutcome twist on the AlternateUniverse variant of the tropes by having many musical numbers [[StylisticSuck be very obviously unrehearsed joke songs]] with terrible melodies or slap-dashed lyrics if not sung by characters like Marceline, who is explicitly shown to be a talented musician.

* ''WesternAnimation/HazbinHotel'' mostly features diegetic songs, with characters commenting on other people singing, but occasionally delves into the other three. For example, the scenery in Vox's half of "Stayed Gone" shows either a TimeCompressionMontage or very fast set changes.

* ''WesternAnimation/HazbinHotel'' mostly features diegetic songs, with characters commenting on other people singing, but it's ambiguous as to whether some of the more abstract imagery that occasionally shows up is actually happening. For example, the scenery in Vox's half of "Stayed Gone" shows either a TimeCompressionMontage or very fast set changes.

* ''WesternAnimation/HazbinHotel'' features diegetic songs. Charlie [[ThePollyanna believes herself to be a metaphorical Disney Princess in a world of fluffy bunnies and unicorns]] instead of actual {{Hell}}. However, while other characters comment on Charlie's songs there is some ambiguity as to whether the other characters' songs are diegetic, all in their heads, or adaptations. In particular the scenery in Vox's half of "Stayed Gone" shows either a TimeCompressionMontage or very fast set changes.

* In the main series for WesternAnimation/HazbinHotel it’s implied that Princess Charlie’s powers, which she inherited from her mother Lilith, turn the world around her into a type 1. This is probably why the residents of Pentagram City get caught up in musical numbers now and then. Other parts of the Hellaverse have been more diegetic.

* ''WebAnimation/HazbinHotel'' features diegetic songs. Charlie [[ThePollyanna believes herself to be a metaphorical Disney Princess in a world of fluffy bunnies and unicorns]] instead of actual {{Hell}}, and writes a song for her hotel pitch in "That's Entertainment" that is extremely reflective of that.

* ''WesternAnimation/TotalDrama World Tour'' is mostly Digetic (except for the part where they plan songs out in advance); but the visuals, such as a cut to Team Amazon playing in a real band or both teams dancing in jumpsuits, are Adaptations even when they're singing the song in real time.
** One could argue that it's a weird mixture of Digetic and Alternate Universe: this is not a world where breaking into song is normal, and the characters explicitly do not prepare in advance or know what their songs will be about. Nevertheless [[ScrewTheRulesIMakeThem when Chris ordains it]], music comes out of nowhere and the characters are able to [[MusicalisInterruptus spontaneously sing]] [[SpontaneousChoreography and dance]] with only an occasional broken rhyme or confused look.

* ''Theatre/TheSoundOfMusic'' follows the Diegetic Hypothesis for most of its songs, most notably the title song, "Edelweiss", "My Favorite Things", "The Lonely Goatherd", and the seemingly improvised "Do-Re-Mi". Some of the others seem to follow the Adaptation Hypothesis, such as "Maria" and the {{Love Theme}}s. (In the movie, Liesel sings "Sixteen Going On Seventeen" with Rolf ''before'' Maria teaches the Von Trapp children how to sing.)

* ''Film/GuardiansOfTheGalaxy2014'' and its sequel aren't musicals ''per se'', but nonetheless they include a lot of songs which they get from Peter Quill's mixtapes, which usually end up being either Diegetic (when he's playing his music) or Adaptation (a song is playing, with the implication that it exists on his tapes, but it's clearly not happening in-universe). The first film starts with Quill dancing to "Come and Get Your Love", but since he's got headphones on, it's functionally the same as an All In His Head song. ''Film/AvengersEndgame'' lampshades this: [[spoiler:Nebula and War Machine time-travel back to this point, but they can't hear the music and only see Quill dancing and singing off-key to nothing like an idiot.]] At one point in the second movie Rocket has an ally play one of Quill's songs for the explicit purpose of accompanying the following fight.

* ''WesternAnimation/PhineasAndFerb'' is definitely a musical world, although an...interesting one. While people do burst into song and dance at random times, Doofenshmirtz has been known to hire back-up singers specifically for this purpose. Also, the MusicalEpisode lampshades it to hell and back.

* The ''Series/{{Buffy|the Vampire Slayer}}'' MusicalEpisode is an example of the "magic spell" subset of the AlternateUniverse Hypothesis. Everyone in Sunnydale starts singing and dancing uncontrollably, as if they're in a musical. They know it's weird, but they can't stop. The culprit turns out to be Sweet, a demon that [[spoiler:Xander]] accidentally summoned. It makes people sing about their hidden feelings, causing various relationship problems, and in some extreme cases the people with the biggest secrets dance until they literally burn up.
--> '''Giles''': I've got a theory, that it's a demon. A dancing demon! No, something isn't right there
--> '''Willow''': I've got a theory, some kid is dreaming, and we're all stuck inside his wacky broadway nightmare!
--> '''Xander''': I've got a theory we should work this out
--> '''All''': It's getting eerie... What's this cheery singing all about?
--->-- Once More With Feeling, the ''Series/BuffyTheVampireSlayer'' Musical episode (from Season 6)

* ''Film/TheCourtJester'' is mostly diegetic, with all the songs being sung by Hawkins, who is himself an entertainer in situations where they mostly make sense, though they also feature some non-diegetic background music."Life Could not Better be" is probably alternate universe, since it is the prologue and takes place outside the action of the story."Outfox the Fox" is diegetic, with Hawkins and his carnival friends working together to put on a show for the outlaws. We even see the outlaws watching the show, and it is made clear that entertaining the men is Hawkin's job. "I'll take you dreaming" is diegetic, since it is a lullaby Hawkins sings to help the baby fall asleep."To Whom do I Hum" is diegetic since Hawkins is singing it to try to surreptitiously give the password, and he is accompanying himself on the lute as he sings it."The Maladjusted Jester" seems to be diegetic, as it clearly begins with Hawkins trying to make up a song on the spot as a distraction (he even hums a few bars from "I'll take you dreaming" while he's thinking) before managing to segue into a song he knows.

* ''Series/StarTrekStrangeNewWorlds'' has this happen in [[Recap/StarTrekStrangeNewWorldsS2E09SubspaceRhapsody Subspace Rhapsody]], with the Alternate World variant; after an experiment with a subspace fold transmits music into it, it creates a quantum uncertainty field where the crew of the ''Enterprise'' literally enter an alternate reality where people sing uncontrollably. It is mentioned the effect extends across the Federation and half the Klingon Empire, but the only singing from outside the ''Enterprise'' to be shown is a communication with another Starfleet ship that turns into both captains singing, and a quick scene of a Klingon bridge crew [[spoiler: singing in K-pop style]].

* ''Series/StarTrekStrangeNewWorlds'' has this happen in [[Recap/StarTrekStrangeNewWorldsS2E09SubspaceRhapsody Subspace Rhapsody]], with the Alternate World variant; after an experiment with a subspace fold transmits music into it, it creates a quantum uncertainty field where the crew of the ''Enterprise'' literally enter an alternate reality where people sing uncontrollably.

* ''Film/{{Hairspray}}'' is a mixture of Alternate Universe and Diegetic, with one or two songs that might possibly be All In Her Head.

* ''Theatre/{{Rent}}'' is mostly Adaptation with some All In Their Heads (e.g. ''Without You'' and ''What You Own''). There are a few diegetic numbers, though, such as ''Your Eyes'' and ''Over The Moon'', and more that ambiguously might be diegetic, e.g. ''Today 4 U'' (which may or may not be a literal performance by Angel). Notably, the character of Roger is a musician who spends most of the musical struggling to write a song, even as he sings many songs - this baffles some viewers who are unfamiliar with the silent assumption of the Adaptation Hypothesis that the songs aren't literally happening.
* ''Theatre/SweeneyToddTheDemonBarberOfFleetStreet'' is largely Adaptation with some All In Their Heads (e.g. Sweeney's portion of ''Johanna (Reprise)'', part of ''Epiphany'') and a couple of seemingly diegetic (Toby's 'advertising jingles' first for Pirelli and then Mrs. Lovett's pie shop and the "Parlor Songs" sequence).
* ''Film/TheProducers'' seems to use every version of this in theirs. They are trying to produce a musical so some of the numbers are deliberately rehearsed, others take place in the real world but don't seem to be acknowledged as such, in fact, some of these have to be Adaptation Hypothesis because its only in a later "real world" number that Bialystock notices his co-producer's singing voice.
* ''Theatre/MammaMia'' combines AlternateUniverse with Diegetic, as several of the songs are either Donna and her friends reprising their old hits, or Donna's friends reprising their old standards to cheer her up.
* ''Film/{{Hairspray}}'' is a mixture of Alternate Universe and Diegetic, with one or two songs that might possibly be All In Her Head.
* ''Theatre/HedwigAndTheAngryInch'' is a rare example of a Diegetic stage musical.
** The movie adaptation, however, mixes in some "All In Their Heads" numbers - "Wig in a Box" is a flashback to an epiphany conveyed as a musical number, and the final four numbers ("Hedwig's Lament," "Exquisite Corpse," "Wicked Little Town" reprise, and ''especially'' "Midnight Radio") are presented in a MindScrew that could be any combination of Diegetic, All In Their Heads, or Adaptation.

* ''Theatre/SpringAwakening'' is mostly All in Their Heads for solo numbers, though group songs seem to make use of the Adaptation Hypothesis.
* ''Theatre/FiddlerOnTheRoof'' seems to have most of the categories. Tevye's monologues are clearly All In Their Heads, while his 'Do You Love Me' with Golde fits into Adaptation Hypothesis. Most of the other songs fit into Alternate Universe.
* ''Theatre/FlyByNightMusical'' is a blend of everything. The narrator's songs have to be adaptational because he isn't a character in the show, Harold writes and sings songs, so some of his are Diegetic and some are All-Maestro, and the rest is either "All in their Heads" or "Adaptation".
* ''Theatre/{{Oliver}}'' is mostly Alternate Universe, though the songs Nancy sings at the Three Cripples Inn ("It's a Fine Life" and "Oom Pah Pah") can fit into Diegetic. "Be Back Soon" and "Pick A Pocket or Two" is a mix of Diegetic and Alternate Universe due to Fagin mentioning "Singing again" after the latter and "tune" is frequently used in the former.
* The songs the Hot Box Girls sing in ''Theatre/GuysAndDolls'' are Diegetic, as is the Mission ensemble's 'Follow The Fold', but most of the other songs are either Alternate Universe or Adaptation Hypothesis.
* Several songs in ''Theatre/OrdinaryDays'' fit the Adaptation Hypothesis, as almost all songs are sung as though the characters are speaking to the audience. For instance, "Fine" has Jason and Claire refer to each other as 'he/she', rather than 'you', and "One By One" is about how nobody pays any attention to Warren, but is sung as if he has an audience paying attention to him.
* In ''Theatre/SeventeenSeventySix'', every song John Adams sings with Abigail is All In Their Heads with a bit of Adaptation Hypothesis (as, in actuality, Abigail was back in Massachusetts and could only communicate with John by writing letters. So the instant two-way communication in those scenes only happens in John's mind). The other songs are either Alternate Universe or Adaptation Hypothesis.
** Adaptation Hypothesis for the majority of it: ''1776'' uses as one of its major sources the writings of the people who were there at the time, to the point of reusing actual text with, at most, modernization of the English.
** Alternate Universe, however, is also valid given how smoothly Thomson inserts himself into the lyrics of "Cool, Cool, Considerate Men." Clearly, he's used to Congress doing this sort of thing.
* ''Theatre/ThePhantomOfTheOpera'' is approximately two-thirds Adaptation/All In Their Head and one-third Diegetic, with the [[ShowWithinAShow "operas"]] and a few other examples like "Music of the Night" (which is basically the Phantom attempting to seduce Christine via VillainLoveSong) happening as they would in real life but mostly with people singing what they would normally say or think to themselves. The film version supports supports the Adaptation Hypothesis by including scenes where characters actually ''speak'' the lyrics rather than sing them (although the result is [[{{Narm}} awkward]] to say the least).
* As the main character in ''Film/TopHat'' is a musical star several songs are diegetic (such as "Top Hat, White Tie and Tails") as part of the various shows he was part of. "Dancing Cheek To Cheek" was an odd example that was simply the character singing lyrics to a song while they were ballroom dancing (two other songs are sung by other in-universe performers). The rest are all part of the Alternative Universe, a character did in fact get in trouble for tap dancing too loudly.
* ''Theatre/{{Six}}'': Unlike most shows, Six is largely diegetic, as to be expected for a musical shaped like a pop concert. The dialogue in Kathrine Howard's roast makes this clear.

* ''Theatre/LadyInTheDark'': With the exception of the [[DreamMelody one song that has been haunting Liza all her life]], which is eventually sung diegetically, all of the musical numbers take place in Liza's head, being concentrated in three long and highly stylized {{Dream Sequence}}s.
* ''Film/ReeferMadness'', as mentioned under film, is "All in their heads," though as less theater companies can afford to do the elaborate pieces that were done for the film, at times it may also be Adaptation. Consider Little Mary Sunshine - Showtime's version dives headlong into a theatrical version of a sex dungeon, while most theater companies simply have Mary engage in a little DoubleStandardRapeFemaleOnMale.
* ''Theatre/TheCatAndTheFiddle'' handled its musical numbers mostly diegetically, with the principal characters being two rival composers and a street singer.
* ''Music in the Air'' tried to give all its songs a more or less diegetic introduction. This turned out awkwardly in some cases: "When The Spring Is In The Air," obviously written in character for TheIngenue Sieglinde, is first sung offstage by a strolling chorus, and "The Song Is You" becomes a backstage serenade that is acted nowhere near as sincerely as its lyrics.
* WordOfGod (in [[http://diamond.boisestate.edu/gas/pinafore/book/chapter_4.html "The Story of HMS Pinafore"]]) placed ''Theatre/HMSPinafore'' as a sort-of Alternate Universe in which people really do sing - there is a "standing rule that no one was ever to say anything to the Captain that could be sung", and the crew do their best to comply. (Cf. Mad Margaret's line in ''Theatre/{{Ruddigore}}'': "They sing choruses in public! That's mad enough, I think!")
* The musical version of ''Theatre/BulletsOverBroadway'' seems to be a mix. A number of the songs, such as "Tiger Rag", "You Rascal You", "Lazy River", and David and Ellen's parts in "Ain't I Good To You", are clearly diegetic. "The Hot Dog Song" seems to be a mix of Diegetic and All In Their Head, with Olive genuinely singing the song to David and Marx while remembering how it was performed back in the day. Some other songs, such as the finale ("Yes, We Have No Bananas"), "Ain't I Good To You", and "Broken Heart For Every Light On Broadway" could just be characters singing songs they heard before while changing some lines to fit their situation-i.e. diegetic. A few songs seem to fall under All In Their Head ("Blues My Naughty Sweetie" seems to go completely unheard by David, and "The Panic Is On" is pretty clearly David having a panic attack), but for the most part, all the others seem to be either Adaptation (appropriately enough) or Alternate Universe.
* ''Theatre/NextToNormal'' is mostly comprised of songs that fit the All In Their Heads Hypothesis. This makes sense as the main character, Diana, is actually bipolar depressive, and [[spoiler:has been hallucinating her son for 16 years]], so the singing really isn't the oddest thing that she imagines. This is most obvious in the song "Wish I Were Here", where both singers are hallucinating through different means, and the song "My Psychopharmacologist And I", which depicts time stopping as Diana starts fantasizing about her doctor. A few notable exceptions are the songs "Everything Else" and "I Dreamed a Dance", where the ''tunes'' are Diegetic, and are from a piano practice and a music box respectively (both of which are plot-relevant), but the ''lyrics'' are clearly in the singers' heads. The song "Aftershocks" also appears to be more of the Adaptation Hypothesis, as the singer is [[spoiler:the personification of a recurring hallucination, who has been erased from Diana's head (effectively killing him)]], making it somewhat hard to claim that the song is in someone's head.
* ''Theatre/PercyJacksonAndTheOlympians'' mostly fits the Adaptation hypothesis, as the musical tries to mirror the way that the books acknowledge the reader's presence. The two most clearcut exceptions to this are the song "D.O.A.", which has Charon explain that her music is the result of all great musicians ending up in the underworld sooner or later, and "The Campfire Song", which seems like a mix of a few hypotheses; the ''tune'' and the chorus are implied to be a diegetic tune that the campers sing often, however each verse fits the All-Maestro cast theory, as a couple of campers need a second to think before they begin singing, and Percy is expected to (and eventually succeeds) in making up a some lyrics on the spot. The Campfire Song also involves Percy insisting that he can't sing, despite doing so in every song prior, which confirms that that particular song is part of a different Hypothesis.
* ''Theatre/{{Hamilton}}'' is generally an example of the Adaptation hypothesis: almost all of the songs involve two or more characters communicating directly, and the songs are clearly not rehearsed in-universe, and the whole musical is told in a modern-day style clearly intended to merely represent what was actually said rather than depict it faithfully. However, it also nods to the Alternate Universe hypothesis in that the characters do occasionally refer to the fact that they are singing (or, more often, rapping): in Aaron Burr, Sir, the revolutionaries press Burr to 'spit a verse, drop some knowledge', and in Farmer Refuted Hamilton riposites 'Don't modulate the key then not debate with me!' (Of course, freestyle rapping is much more a real thing than freestyle singing, but it's hard to think of any setting in which ''cabinet debates'' are settled via rap as anything other than an alternate universe.) However, some songs are clearly all in the character's heads, such as Helpless or Hurricane. Also, some songs flip between different hypotheses: The Room Where It Happens starts with a straightforward conversation between Hamilton and Burr, then segues into a more narrative song as the characters explain that nobody really knows what happened in the room complete with demonstrations of what might have gone down, and ends with Burr soliloquising about his own motivations in his head.
* ''Theatre/TheSoundOfMusic'' follows the Diegetic Hypothesis for most of its songs, most notably the title song, "Edelweiss", "My Favorite Things", "The Lonely Goatherd", and the seemingly improvised "Do-Re-Mi". Some of the others seem to follow the Adaptation Hypothesis, such as "Maria" and the {{Love Theme}}s. (In the movie, Liesel sings "Sixteen Going On Seventeen" with Rolf ''before'' Maria teaches the Von Trapp children how to sing.)
* ''Theatre/TheWiz'' seems to follow the Alternate Universe hypothesis for most of the play's numbers. In the screen versions, "You Can't Win" (which didn't appear in the original Broadway production) provides a Diegetic example, while songs that Dorothy sings when she has the set all to herself appear staged in a way that suggest that they occur All In Her Head. [[Film/TheWiz The movie]] also uses "The Feeling That We Have" as a Diegetic example.

* ''Film/{{Labyrinth}}'' is primarily Alternate Universe ("As the World Falls Down" is partially All In Their Heads). All the song-and-dance numbers take place in the MagicalLand the heroine is swept into, and unlike most musicals, aren't spread out among the primary characters. A WackyWaysideTribe gets one and the primary villain gets the other three, suggesting that singing is simply a way they express themselves.

* ''Film/{{Enchanted}}'' is definitely of the Alternate Universe type. Giselle is from another universe and sometimes has the ability to make our universe act according to her universe's rules. When everyone starts singing in Central Park, Robert wonders where they learned the song.

* ''Film/MoulinRouge'' is primarily an alternate universe, with a setting that lends itself well to diegetic numbers. Also the story is being typed up by Christian, overlapping with the 'All In Their Head' somewhat.

* ''Film/MontyPythonAndTheHolyGrail'' is mostly diegetic. The minstrel and his band are clearly singing in-universe about Brave Sir Robin. The ''Knights of the Round Table'' song may appear to be something else, but as part of the song is about how they like to dress up, sing and dance, it's clear that the knights actually are singing and dancing. Which is why Arthur decides not to go to Camelot, as it is "a silly place." The Swamp Castle scenes are probably Alternate Universe, since music will start out of nowhere when Prince Herbert wants to sing, but stops when the King tells it to.
* ''Film/TheMask'' is an alternate universe example. A little magic from the title character can make people break out in [[SpontaneousChoreography Spontaneous Song And Dance]]. In fact, people struggle to maintain control as they're slowly forced to sing.
* The short film ''7:35 in the Morning'' is a diegetic example, and arguably a {{deconstruction}}. A woman stopping at a diner is surprised when everyone starts singing to her. As it turns out, a single person wrote the whole song in an attempt to woo her... and he's threatening to blow up the diner if anyone doesn't sing along.
* ''Film/SantaAndTheIceCreamBunny'' is most likely diegetic (though the producers likely didn't give it much thought). All the musical numbers except for one have no background accompaniment, and the singing sounds ''exactly'' the way it would in real life.
* ''Film/SinginInTheRain'', being a movie about making a movie musical, is a mixture of Diegetic ("Fit as a Fiddle", "All I Do Is Dream of You", "Beautiful Girl", "Would You?") and Alternate Universe ("Make 'Em Laugh", "You Were Meant For Me", "Moses Supposes", "Good Morning'", "Lucky Star"). "Broadway Melody Ballet" is a hybrid of All In Their Heads and Diegetic, as it occurs in a scene where Don and Cosmo are describing a proposed musical number to their studio head. The title song itself plays out as Alternate Universe, but since it actually originated from a movie musical called "The Hollywood Revue of 1929", it could be regarded as Diegetic if one presumes that said musical exists in-universe and had been seen by the characters.
* ''Film/{{Spectacular}}'' is Diegetic. All of the songs in the movie are presented as performances.

* ''Film/ReeferMadnessTheMusical'' (not the early '30s ScareEmStraight film), certainly is "All in their heads." The opening song shows the parents beginning to panic over the thought of their children becoming monsters for smoking marijuana. Then their kids become literal ghouls and mob the parents, complete with dance choreography from Music/MichaelJackson's Thriller. At the end of the song, the ghouls vanish and the parents are firmly in the hands of an anti-pot activist. The silliness only goes up from there.

* ''[[https://en.wikipedia.org/wiki/Leto_(film) Leto]]'', a JukeboxMusical about a brief period in the lives of ViktorTsoi and several other notable figures of underground Soviet rock, is a mixture of Diegetic and All In Their Heads, with the musical numbers being either in-universe performances by the characters or [[FantasySequence Fantasy Sequences]]. Whenever one of those sequences happens, a character known only as "[[AuthorAvatar the Sceptic]]" shows up to point out that "this didn't actually happen".
* ''Film/TheCourtJester'' is mostly diegetic, with all the songs being sung by Hawkins, who is himself an entertainer in situations where they mostly make sense, though they also feature some non-diegetic background music."Life Could not Better be" is probably alternate universe, since it is the prologue and takes place outside the action of the story."Outfox the Fox" is diegetic, with Hawkins and his carnival friends working together to put on a show for the outlaws. We even see the outlaws watching the show, and it is made clear that entertaining the men is Hawkin's job. "I'll take you dreaming" is diegetic, since it is a lullaby Hawkins sings to help the baby fall asleep."To Whom do I Hum" is diegetic since Hawkins is singing it to try to surreptitiously give the password, and he is accompanying himself on the lute as he sings it."The Maladjusted Jester" seems to be diegetic, as it clearly begins with Hawkins trying to make up a song on the spot as a distraction (he even hums a few bars from "I'll take you dreaming" while he's thinking) before managing to segue into a song he knows.
* ''Film/{{Enchanted}}'': Andalasia is an Alternate Universe where singing is normal. When Giselle goes to New York, where singing is ''not'' normal, she can spread this ability to other people, as shown in "That's How You Know". However, Robert, due to his grumpiness, isn't affected. "So Close" is the only diegetic example, since it's sung during a dance.
* ''Film/TickTickBoom'' is a combination of Adaptational and Diagetic. The movie is a the story of Jonathan Larson's life intercut with a performance of his minimalist play "tick tick...BOOM" which he wrote as a semi-fictionalized autobiography. The songs sung during the play are most definitely Diagetic, but the songs sung during the "real" events fall under Adaptational. The film's take on "Come To Your Senses" introduces some All in their Heads as well, since while Karessa is performing it in-universe, Jonathan imagines Susan singing it, resulting in a DistantDuet.
* ''Film/Spirited2022'': The afterlife is a diegetic example - an onboarding liaison for new recruits to the spirits’ organization tells the recently deceased team member that the afterlife is basically one big musical and the spirits are all aware of their numbers. The living, meanwhile, operate on Alternate Universe rules: Briggs’ first musical number is a big flashy performance with elaborate sets and back-up dancers that all disappear when he finishes singing. As the movie goes on, Briggs seems to be more and more aware of the numbers.
* ''Film/WalkTheLine'' is Diegetic, as Johnny Cash is a professional singer on tour with his group. Each musical number depicted in the film occurs at a point that is professionally or personally important to Johnny Cash' life. (For example, his first audition, his first public performance, his comeback performance, asking June to marry him on stage, etc.)

* Most of the ''Franchise/{{Barbie}}'' films use the Alternate Universe type. ''WesternAnimation/BarbieAndTheDiamondCastle'', however, is mostly Diegetic (despite being promoted as a "musical fairytale"), since it focuses around two girls on a mission to bring music back to their world. ''WesternAnimation/BarbieInRockNRoyals'' is also Diegetic, with all the numbers being performed as acts, performances, or camp activities.
* ''WesternAnimation/TheNightmareBeforeChristmas'' could be either Alternate Universe or Adaptation for most of the movie; it ''could'' plausibly be normal for the people of the holiday towns to express themselves by singing (at no point does anyone from the human world sing) but no one ever comments on it. Exceptions:
** "This Is Halloween" is pretty clearly Diegetic, since the citizens of Halloweentown plan a big event every Halloween, and the way the Mayor walks up to Jack's doorstep humming the tune the next day points toward the characters at least knowing the song in-universe.
** "What's This?" fits as All In Their Heads, because even though Jack's running around singing and making a spectacle of himself, the only time anyone even comes close to noticing him is when he passes within a hair's breadth of them.
** "Poor Jack" could be whatever of the three. Diegetically speaking, he starts singing after having heard the street musicians playing their tune, so he might be improvising on this melody he's heard many times before and seems to fit so well his mood. The song seems to start as an Inner Monologue All In Jack's Head, but Sally is supposed to be witnessing the song, and the key to her deeper understanding of Jack's character is having heard the lyrics, so he must be speaking out loud. He might, however, be just speaking, not singing.
** "Sally's Song" is similar, she does walk past the same street musicians and said musicians seem to produce the background music for her song.
** "Oogie Boogie's Song" can either be diegetic or Alternate Universe, since it isn't clarified if the background music is produced by one of the casino machines in Oogie's lair, in which case he's improvising the lyrics on a preexisting tune (that's pretty much diegetic), or if he's singing that like if he was talking.
* ''WesternAnimation/TheKingsBeard'' operates on a variant of the AlternateUniverse hypothesis: spontaneous song numbers are normal in the Mirrored Kingdom, but nowhere else, and outsiders to the Kingdom consider it to be ridiculous, eccentric behaviour at first. Ronnie spontaneously starts singing as a sign that he's embraced living in the Mirrored Kingdom.
* ''WesternAnimation/MyLittlePonyEquestriaGirls'', like the main ''Friendship is Magic'' universe, makes use of all four types:
** [[WesternAnimation/MyLittlePonyEquestriaGirls The first film]] is almost completely All in Their Head, with almost every song being done during a montage, reflecting the characters' inner thoughts. The only song that averts this is the Cafeteria Song, which is diegetic, with the characters having rehearsed prior to the scene.
** ''[[WesternAnimation/MyLittlePonyEquestriaGirlsRainbowRocks Rainbow Rocks]]'' is completely diegetic, with everything except the opening theme being performed by the characters within the context of the film's plot, though several cut away to various scenes, or during a song emphasizing the BattleOfTheBands theme, to ''literal'' battling between bands on the high points of the song.
** ''[[WesternAnimation/MyLittlePonyEquestriaGirlsFriendshipGames Friendship Games]]'' is a mixture; Human Twilight's IWantSong and Cinch's villain song are Alternate Universe; "ACADECA" is mostly All in Their Head, with a hint of Alternate Universe and Adaptation.

* ''WesternAnimation/AllDogsGoToHeaven'' seems to fall under AlternateUniverse Hypothesis. Musical numbers aren't questioned all that often and occur in all versions. However, there are some more wild numbers, but one is the TropeNamer for BigLippedAlligatorMoment and most of the others involve a legit RealityWarper being the one singing.
* ''WesternAnimation/AGoofyMovie'' is a mix of Diegetic, Adaptation, and AlternateUniverse. For the diegetic part, "Stand Out" and "[=I2I=]" are InUniverse pop songs, while "Lester's Possum Park" occurs during a show. "After Today" and "Nobody Else But You" happen with no explanation and may very well be mere representations of the singers' feelings and thoughts. "On the Open Road" is probably AlternateUniverse as Goofy starts singing it after noticing a beat in his car, explicitly tells Max to "sing along," and is heard humming it in the film's ending.
* ''WesternAnimation/{{Coco}}'' is Diegetic; all of the songs are performed as part of an act or for an audience.

* ''WesternAnimation/TheRugratsMovie'': "This World is Something New to Me" is probably All in Their Heads, since babies are established not to be even able to speak BabyLanguage when they're newborn. Also, the babies don't seem to notice that the other babies are singing.
* ''WesternAnimation/{{Sing}}'': The songs are Diegetic, since it's about a singing competition.

* ''Franchise/TheMuppets'' franchise plays this multiple different ways:
** In ''Film/TheMuppetMovie'', "Rainbow Connection" is Diegetic, since Kermit being complimented on his singing is what kickstarts the plot. "Never Before, Never Again" is definitely All In Miss Piggy's Head, complete with fantasy visuals. The rest are less clear, but probably Adaptation (since it's established that it's a movie-within-a-movie and "approximately how it happened").
** ''Film/TheGreatMuppetCaper'' is pure Alternate Universe. Since the movie establishes right from the start that there's NoFourthWall, they're singing because it's a musical, and they ''know'' it's a musical!
** ''Film/TheMuppetsTakeManhattan'': All the songs that are part of ''Manhattan Melodies'' are Diegetic. "Rat Scat", which the rats sing while cooking, probably is as well. "I'm Gonna Always Love You" is another Piggy fantasy, sung by the Muppet Babies who explicitly ''don't exist'' in this setting, so All In Her Head. That leaves "You Can't Take No For an Answer" and "Saying Goodbye". The former could be All In Dr Teeth's Head, but the latter, with characters having conversations in song, pushes it towards Alternate Universe or Adaptation.
** ''Film/MuppetTreasureIsland'' is a mixture, but mostly Alternate Universe combined with a [[BreakingTheFourthWall removable fourth wall.]] It's usually acknowledged that they're singing ("Sailing for Adventure" features Samuel Arrow cautioning them not to get sloppy just because they're singing) but no one seems to find anything strange about it. (Arguably TruthInTelevision for that one song, but it's got the wrong rhythm for a [[MusicalChores sea shanty]].)
*** "Professional Pirate" is Diegetic, since Long John Silver tells his men to "show 'em you've been practicing".
*** "Cabin Fever" seems to be All In Their Heads, but only because the crew's been driven temporarily insane. [[OrWasItADream Or was it?]] Maybe the insanity is what got them all singing about it? The question is never answered. Afterwards "Cabin Fever," [[ExactlyWhatItSaysOnTheTin Clueless]] Morgan actually asks Polly the Lobster, "What was that song that just happened?" Polly thinks he's crazy, indicating Polly wasn't aware of the song. This seems to indicate that it was All In Their Heads for the singers, but also for Morgan even though he wasn't singing.
** ''Film/TheMuppets2011'' is mostly Alternate Universe (The reprise of [[CrowdSong "Life's a Happy Song"]] ends with the crowd collapsing from exhaustion; the Muppets are baffled by Tex Richman's rap), while the songs performed during the fundraiser are diegetic (just as they would be in RealLife).
* ''Film/WalkTheLine'' is Diegetic, as Johnny Cash is a professional singer on tour with his group. Each musical number depicted in the film occurs at a point that is professionally or personally important to Johnny Cash' life. (For example, his first audition, his first public performance, his comeback performance, asking June to marry him on stage, etc.)
* The film version of ''Film/{{Chicago}}'' falls under All In Their Heads. Except for those numbers actually performed on stage, all the songs are the product of Roxie Hart's imagination, to the point where the song "Class" was removed because there was no way the director could make it fit.
* ''Theatre/NineMusical'' is done by the same director, and does the same thing. Since it's an adaptation of ''8 1/2'', this works pretty well. The protagonist is having a mid-life crisis and is a creative film director.
* ''Film/{{Enchanted}}'' is definitely of the Alternate Universe type. Giselle is from another universe and sometimes has the ability to make our universe act according to her universe's rules. When everyone starts singing in Central Park, Robert wonders where they learned the song.
* ''Film/TheWeddingSinger'' is of the Diegetic type. Most of the songs are performed by Robbie in his professional capacity. The only other one is when he is trying to win back Julia; many people in RealLife sing when courting a woman.
* Many people refuse to count ''Film/OBrotherWhereArtThou'' as a musical because the songs don't come out of nowhere, but it would fit pretty easily as a diegetic musical.

* ''Film/{{Once}}'' is pretty clearly a Diegetic musical, as the characters are both musicians performing songs for each other and recording an album together, but many of the songs have lyrics relevant to the plot.
* ''Film/{{Dreamgirls}}'' dabbles in all four of these categories, but sticking mostly to AlternateUniverse and Diegetic. The film seemed to be purely Diegetic for the first hour or so, then suddenly began to dabble in the other categories with no warning or explanation.
* ''Film/MoulinRouge'' is primarily an alternate universe, with a setting that lends itself well to diegetic numbers. Also the story is being typed up by Christian, overlapping with the 'All In Their Head' somewhat.
* ''Film/LetItShine'' is Diegetic. All of the music is presented as a rehearsal or performance, mostly by Cyrus or Roxie.
* ''Film/LittleShopOfHorrors'' the film is definitely an Alternate Universe, but songs like "Skid Row" and "Suppertime" could be All in Their Heads or an Adaptation based on the telling of the GreekChorus composed of three Motown songstresses. Audrey II's lyrics could be the Diegetic compositions of a very musical alien. Oh, and [-[[MusicalisInterruptus "If you two could stop singing for just one minute..."]]-]
* ''Film/{{Fame}}'' (1980) is mostly diegetic, as is appropriate for a film about a school for the performing arts, but one number, ''Hot Lunch'', seems to spill into Alternate Universe territory. An impromptu bit of music by a few students in the cafeteria gradually enlarges to encompass the entire school, spilling out into the surrounding city streets until it literally stops traffic. Somewhat justified, perhaps, in that it ''is'' a school for the performing arts, whose student body might be better prepared for sudden improv than your average high school.
* ''Film/PenniesFromHeaven'' (1978 TV miniseries and 1981 Film) -the many lip-synced musical numbers are all in the heads of the main characters.
* ''Film/MontyPythonAndTheHolyGrail'' is mostly diegetic. The minstrel and his band are clearly singing in-universe about Brave Sir Robin. The ''Knights of the Round Table'' song may appear to be something else, but as part of the song is about how they like to dress up, sing and dance, it's clear that the knights actually are singing and dancing. Which is why Arthur decides not to go to Camelot, as it is "a silly place." The Swamp Castle scenes are probably Alternate Universe, since music will start out of nowhere when Prince Herbert wants to sing, but stops when the King tells it to.
* ''Film/TheMask'' is an alternate universe example. A little magic from the title character can make people break out in [[SpontaneousChoreography Spontaneous Song And Dance]]. In fact, people struggle to maintain control as they're slowly forced to sing.
* The short film ''7:35 in the Morning'' is a diegetic example, and arguably a {{deconstruction}}. A woman stopping at a diner is surprised when everyone starts singing to her. As it turns out, a single person wrote the whole song in an attempt to woo her... and he's threatening to blow up the diner if anyone doesn't sing along.

* In ''Film/DancerInTheDark'', all the musical numbers are explicitly depicted as daydreams of the main character, who as it happens loves movie musicals.
* ''Film/AcrossTheUniverse2007'' combines most if not all of these types, sometimes switching from one to another mid-song; for example, "I Am the Walrus" starts out diegetic, with Bono singing a song for his party guests, and then quickly dissolves into All In Their Heads [[MushroomSamba as the hallucinogens kick in...]]
* ''Film/SantaAndTheIceCreamBunny'' is most likely diegetic (though the producers likely didn't give it much thought). All the musical numbers except for one have no background accompaniment, and the singing sounds ''exactly'' the way it would in real life.
* ''Film/{{Labyrinth}}'' is primarily Alternate Universe ("As the World Falls Down" is partially All In Their Heads). All the song-and-dance numbers take place in the MagicalLand the heroine is swept into, and unlike most musicals, aren't spread out among the primary characters. A WackyWaysideTribe gets one and the primary villain gets the other three, suggesting that singing is simply a way they express themselves.
* ''Film/SinginInTheRain'', being a movie about making a movie musical, is a mixture of Diegetic ("Fit as a Fiddle", "All I Do Is Dream of You", "Beautiful Girl", "Would You?") and Alternate Universe ("Make 'Em Laugh", "You Were Meant For Me", "Moses Supposes", "Good Morning'", "Lucky Star"). "Broadway Melody Ballet" is a hybrid of All In Their Heads and Diegetic, as it occurs in a scene where Don and Cosmo are describing a proposed musical number to their studio head. The title song itself plays out as Alternate Universe, but since it actually originated from a movie musical called "The Hollywood Revue of 1929", it could be regarded as Diegetic if one presumes that said musical exists in-universe and had been seen by the characters.
* ''Film/{{Spectacular}}'' is Diegetic. All of the songs in the movie are presented as performances.

* ''Film/PitchPerfect'', a film about collegiate a capella, is mostly Diegetic, with some All-Maestro Cast. The Bellas are shown practice their choreography and harmonizing. When Beca sings another song during SemiFinals, Aubrey calls her out for breaking from routine. However, during the Riff-Off, some songs seem to practiced or familiar, while others are done by the singers as improv.
* ''Film/RepoTheGeneticOpera'' has almost no spoken dialogue, being an opera (or a rock opera, at least). Most of the movie is Alternate Universe, but it gets a little mixed up when they actually get to the Genetic Opera. While Mag and Amber's songs are clearly meant to be Diegetic, "We Started This Op'ra Shit" is a mix (most of the song is meant to be a rehearsed performance, but the single mom's testiominal isn't) and they switch back to Alternate Universe after the Genetic Opera ends (even though the characters are still onstage). "Seventeen" is partly All In Their Heads; while it involves an argument between Shilo and her dad, Shilo also sings it directly into a microphone with a backing band that includes Joan Jett! And Grave Robber is a special case altogether, since half of his songs are exposition sung [[BreakingTheFourthWall directly to the audience.]]
* ''Film/ReeferMadnessTheMusical'' (not the early '30s ScareEmStraight film), certainly is "All in their heads." The opening song shows the parents beginning to panic over the thought of their children becoming monsters for smoking marijuana. Then their kids become literal ghouls and mob the parents, complete with dance choreography from Music/MichaelJackson's Thriller. At the end of the song, the ghouls vanish and the parents are firmly in the hands of an anti-pot activist. The silliness only goes up from there.
* ''Film/ScottPilgrimVsTheWorld'' is not a musical, but quite a few musical numbers come up and are important to the plot. They are always both diegetic and in an Alternate Universe where the world follows video-game and comic-book like rules. For example, one set of performers tears the roof off the building, meaning they stun the crowd -and- tear the roof clean off the building.

* ''Film/TeenBeachMovie'', or rather ''[[ShowWithinAShow Wet Side Story]]'', is an Alternate Universe variety that the protagonists Mack and Brady are [[TrappedInTVLand trapped in]], and seems to [[FisherKingdom force musical numbers on visitors]].
* Save for two songs that are diegetic (both versions of In The Flesh, where Pink is seen singing in front of an audience), the film version of ''Music/TheWall'' is purely adaptational, as is suggested by the opening song, where Pink tells the audience that to see [[BeneathTheMask his true self]], they have to claw their way through his disguise. Also, several songs, such as "Comfortably Numb" only work in an adaptational sense (in the case of "Comfortably Numb", though singing, Pink admits he can't hear what the doctor is saying, yet he seems to respond to him as if he can), though others, like "The Trial", work best in an all in his head form.

* ''Film/CoverGirl'' is mostly Diegetic, with a couple of exceptions: "Make Way for Tomorrow" is Alternate Universe, and the "Alter Ego" dance is All In Danny's Head. "Long Ago and Far Away" is ambiguous--it could be Diegetic (improvised to Genius's piano playing), or it could be Alternate Universe.

* ''Film/{{Aladdin 2019}}'': "Prince Ali" and "Friend Like Me," as in the original, are 100% diegetic -- performances given in-universe that other characters can and do fully see, hear, and react to. "Arabian Nights" is also ''definitely'' diegetic in this version, as the "merchant" begins to tell a story by singing it to his children after they specifically ask him to sing. Aladdin's songs fit Adaptation or All in his Head -- a musical rendering of his thoughts and feelings. Jasmine's song "Speechless" is clearly All in her Head, as the guards restraining her keep walking without the slightest reaction to their prisoner bursting into song (until they vanish and everyone else in the scene freezes to indicate time isn't even really passing).
* ''Film/GuardiansOfTheGalaxy2014'' and its sequel aren't musicals ''per se'', but nonetheless they include a lot of songs which they get from Peter Quill's mixtapes, which usually end up being either Diegetic (when he's playing his music) or Adaptation (a song is playing, with the implication that it exists on his tapes, but it's clearly not happening in-universe). The first film starts with Quill dancing to "Come and Get Your Love", but since he's got headphones on, it's functionally the same as an All In His Head song. ''Film/AvengersEndgame'' lampshades this: [[spoiler:Nebula and War Machine time-travel back to this point, but they can't hear the music and only see Quill dancing and singing off-key to nothing like an idiot.]] At one point in the second movie Rocket has an ally play one of Quill's songs for the explicit purpose of accompanying the following fight.

* ''Film/Annie1982'': The "Betcha" song is definitely Alternate Universe, since Miss Hannigan asks, "Do I hear singing in here?". The rest are unknown.

* ''Film/TheBluesBrothers'' is mostly diegetic, with actual bands and musicians doing rehearsed performances. But then you have Aretha Franklin randomly bursting into song in a diner accompanied by background singers, and people flooding the streets to do a choreographed dance when Ray Charles belts out a number. "Minnie the Moocher" is an odd case where the ''music'' is clearly diegetic ([[ContrivedCoincidence they just happened to know how to play that exact song perfect the first time]]), but the ''outfits'' worn by the band are clearly part of an AlternateUniverse: they instantly change from their regular clothes to white vests when the song starts and suddenly reverted when it ends between shots, without any scene change whatsoever.