Like Brother And Sister / Real Life

• While commonly cited in situations like this, the Westermarck Effect is actually pretty questionable. It's based on Edward Westermarck's study of the kibbutzim where children were reared somewhat communally in peer groups based on age, not biological relations. He found that these kids rarely went on to marry each other. On this basis, he concluded that this is what happens with siblings—children who know each other during their early childhood will rarely develop any romantic interest later in life. Science Marches On however, and in a later study by Eran Shor and Dalit Simchai found that kibbutzim kids were often attracted to their peers. That people rarely marry their childhood crushes is not evidence they don't have childhood crushes.
• As of Avengers: Endgame, Chris Evans and Scarlett Johansson have worked together on a total of eight movies (including that movie, the first Avengers, Winter Soldier, Age of Ultron, Civil War and Infinity War) for about 15 years since 2004's The Perfect Score. They haven't dated in real life and the only time they played actual romantic interests for each other was 2007's The Nanny Diaries.
• Mark Hamill admitted that he had this relationship with Carrie Fisher, although of the more vitriolic kind ("...like a sister to me, sometimes we don't speak for years, but I would lay down my life for her"). On Twitter he frequently referred to her as his beloved "space sister," and in the 2010s they did silly things like posing for 'Skywalker family photos'. His remarks about their relationship are considerably Harsher in Hindsight, since Fisher's unexpected death in 2016 left Hamill in almost Stunned Silence. His comments on social media have made it clear that he was, and remains, heartbroken by her loss.
• Leonardo DiCaprio and Kate Winslet, having been very close friends since Titanic and collaborating again in Revolutionary Road, remain this and nothing else. Kate's kids call him "Uncle Leo," and for a kissing scene in Revolutionary Road, Leonardo stated that it felt slightly weird because kissing Kate was like kissing a family member.
• Daniel Radcliffe, Rupert Grint and Emma Watson of Harry Potter fame all grew up around each other while shooting the 8-film saga over the course of 10 years to the point where they do sort of regard each other as surrogate siblings, to the point where when all three got a healthy dose of Squick while filming kissing scenes for the later movies in the saga.
• Arguably the luckiest of King Henry VIII's wives was Anne of Cleves. Misled by flattering portraits on both ends and a need for a political alliance, they married. As soon as it was time to consummate things, the pair found out that there was absolutely zero attraction and Henry opted for an annulment. Anne was sensible enough to sign the annulment papers with all due haste (and probably a sigh of relief); she thus kept in good standing with Henry, who liked her very much and got along well with her as a person even though there was no physical attraction, and became known as "the King's beloved sister." For the remainder of Henry's reign, he decreed that apart from his wife (whoever that was at the moment) and daughters, Anne would be the highest ranked woman in the entire kingdom. She was invited to all the events at court, provided with a household and income by the crown, and was very close with both of Henry's daughters, even participating in the procession when Mary I became queen.
• David Faustino denied that there was ever any romance between him and Christina Applegate on Married... with Children, instead defining their relationship as this trope. Furthermore, it applies doubly for them both in real life, as David doesn't have any sisters and Christina is an only child.
• Jennette McCurdy has specifically said that kissing Nathan Kress feels like kissing a brother, and it's part of the reason some fans see the relationship of Sam and Freddie in the fifth season of iCarly as being subject to Shipping Bed Death due to the lack romantic chemistry.
• Joel Courtney and Katherine McNamara have been close friends for years and worked together regularly on movie reviews and interviews.
• During an interview with Craig Ferguson, Jet Li stated that actress Michelle Yeoh, with whom he has an extensive working history, is "like a brother to me".
• You could describe the relationship between Johnny Depp and Helena Bonham Carter like this.
• Nathaniel Parker, who plays the title character of The Inspector Lynley Mysteries, outright stated that he sees co-star and close friend Sharon Small, who plays Lynley's beloved partner Barbara Havers, as his little sister. This does not, it must be noted, stop him from shipping their two characters like it was going out of style.
• While Law & Order: Criminal Intent left the actual relationship between Robert Goren and Alexandra Eames somewhat ambiguous, Vincent D'Onofrio (Goren) has stated that this is the real life relationship he shares with Kathryn Erbe (Eames).
• NUMB3RS star Dylan Bruno (Colby Granger) has stated that this is how he feels about his co-star Diane Farr (Megan Reeves), owing to the fact that she used to date his brother. Arguably this comes across in their characters' dynamic as well.
• Bradley McIntosh and Rachel Stevens out of S Club 7 remarked that having to kiss in the movie Seeing Double made them react like this. In the movie Bradley is supposed to be attracted to a clone of Rachel but not the real one, and in interviews he said filming the kiss scene was like kissing his sister.
• Jack White and Meg White of The White Stripes are actually ex-spouses, but have referred to themselves as siblings. Not like siblings, but as siblings. Let that sink in.
• Judy Garland and Mickey Rooney starred in nine movies together as teenagers. They remained friends ever after, and Rooney had a serious breakdown when Garland was reported dead.
• Jennifer Lawrence and Josh Hutcherson starred as the lead couple in four movies of The Hunger Games franchise together, and the chemistry they display in interviews has resulted in massive shipping by fans; even their film director ships them. Despite this, both have said in an interview that they are like brother and sister.
  • In turn, Tom Blyth and Rachel Zegler became very close on the set of the prequel and while given Actor Shipping while also playing Love Interests, they don't share a romantic connection in spite of those things.
• Homosexual people very often develop sibling-like relationships with their friends of the opposite sex.
• There is a midrash about a matron asking a rabbi why God put Adam to sleep before creating Eve. The rabbi said "he tried doing it while Adam was awake, but the process was too disgusting for the man to love her". The matron noted that she can confirm it — she was supposed to marry a relative of hers, but due to the fact they grew up together, she became ugly in his eyes, so he married another girl, one not nearly as pretty.
• A particularly nasty example of this trope occurred in 16th century France. At the time, marriages among royalty were arranged, and some of the unions were less than joyous. As a result, someone got the bright idea that if the young princes were raised with their respective fiancées from an early age, they would become accustomed to one another and grow up to form stable marriages. Unfortunately, since the couples weren't too closely related by blood or adoption, no one counted on the Westermarck effect described above. Thus, when it came time for the couples to grow up and get married, they saw each other as this trope, and the process of trying to produce heirs squicked them so much that they did so as little as possible, if at all. The nasty part comes in when, due to lack of heirs, the ruling Valois dynasty died out, and the resultant Succession Crisis led to civil war.
• While playing romantically-involved characters in Scream (2022), Melissa Barrera and Jack Quaid proved to just be very close friends in real life through set pics that they'd taken together.
• It's well understood that voice actress Yukana often displays her Big Sister Instinct to the popular voice actor Tomokazu Sugita. According to a radio show in 2010, she helped him when his original talent agency dissolved in the early 2000s, and she still helps him through hard times. In fact, Sugita even mentions that the two people who scolded him for not eating enough meat were Yukana and his mom.
• Canadian ice dancing duo Tessa Virtue and Scott Moir, in spite of showing a chemistry that gave them two Olympic golds and has been described as downright steamy, have declared themselves to be this, with their only attempt at romance happening when they were just kids. The shipping had gotten to the point that when Scott announced he was engaged to another skater, thousands were heartbroken and unjustly targeted his fiancée.
• According to Charmian Carr's autobiography, Forever Liesl, this was/is the relationship between all seven of the actors who portrayed the von Trapp children in The Sound of Music. In the book, she describes how the film siblings would have regular get-togethers and were well acquainted with each other's real life families. Carr passed away in 2016, and Heather Menzies (Louisa) followed her in 2017, but the remaining five continue to be part of each other's lives in the same manner.
• Patrick Wilson and Vera Farmiga, who play Ed and Lorraine Warren in The Conjuring Universe, have described their relationship like this. While they were already friends beforehand, Farmiga having worked and become good friends with Wilson's wife Dagmara Domińczyk^note on Farmiga's directorial debut Higher Ground, they have become incredibly close through their work in the franchise. Farmiga spelled it out in an interview:
  Vera: We are family at this point. Patrick knows the deepest parts of me, he’s in the inner circles of my life. We adore each other, and we adore each other’s families. We have so much in common. That deep friendship is a gift from God.
• The Witcher (2019) costars Henry Cavill (Geralt) and Freya Allan (Ciri) are indicated to have developed this bond behind the scenes of the Netflix series; it translates well to the screen, as their characters have a very father-daughter relationship. There are a number of interviews in which Allan talks about how Cavill is a mentor to her with regards to handling fame and jokes about him offering to beat people up for her. Much like the David Faustino example, the trope lands particularly strongly because Cavill has four brothers and no sisters, while Allan has kept her family's identities strictly private, so it's unknown if she has any siblings at all.
  • The same is also true of Anya Chalotra (Yennefer) and Joey Batey (Jaskier), who frequently do interviews together. They have stated that they are best friends both on and off the set.
• Marvin Gaye and Tammi Terrell formed this relationship during their time as singing partners. After Tammi's death from a brain tumour Gaye was the only person from Motown that her mother allowed to attend the funeral because she knew he genuinely cared about Tammi.
• Legendary British ice dancers Jayne Torvill and Christopher Dean of "Bolero" fame — still considered the greatest ice dancing pair to ever compete — were never romantically involved, no matter what the tabloids try to tell you; Jayne has been married to a non-skater since the early '90s^note sound engineer Phil Christensen, whom she met on one of their post-Olympic professional tours, while Chris was married to American skater Jill Trenary for over a decade and has been involved since 2011 with their longtime mutual friend Karen Barber, also a British ice dancer^note she competed with partner Nicky Slater on the competition circuit alongside Torvill and Dean in the mid-'80s. They are, however, the best of friends to this day; apparently they still talk to each other almost every day, even when living on separate continents, and when Jayne had to take the ice solo for a Dancing On Ice performance after Chris injured his knee, she admitted to needing "a quick cuddle" from her longtime partner before going on because she doesn't like skating without him. Awww!