Fake Nationality: English actor Jeremy Irons playing two Canadians, though it's not impossible that they could have been born in England and immigrated to Canada at a young age. Given he never makes any attempt to hide his native accent, this is likely to be the case.
William Hurt was Cronenberg's first choice to play the twins. He regretted turning it down but had a scheduling conflict. He later commented about turning down the roles by saying that he "had a hard enough time playing one character, let alone two". Robert De Niro turned the roles down because he didn't feel comfortable playing a gynecologist.
Margot Kidder was Cronenberg's second choice for playing the role of Claire Niveau.
Working Title: Gemini. The studio didn't like it, and so switched to Twins. This was changed to Dead Ringers after Ivan Reitman, who had produced two of Cronenberg's early films, approached David Cronenberg about purchasing the rights to use the title Twins, which was then used for his comedy film.
Sketch comedy series
Cowboy BeBop at His Computer: Unlike the well-researched Star Trek/Star Wars/Doctor Who sketches, the TV takes on the films of The Lord of the Rings and Harry Potter tended to fall into this — for example, Frodo's said to be on a quest to find the One Ring, and the Harry Potter and Voldemort impressions sound nothing like those in the films. (The radio edition's voices for the Harry Potter characters predated the first film, and they stuck with those even after it was released.) Interestingly, the Michael-Gove-As-Gollum impressions, while not sounding much like Gollum does in the films, do bear a striking resemblance to the Gollum from the older BBC audio dramatization of the books.
Duelling Works: Most of the same impressionists starred in 2DTV which aired on ITV around the same time and was basically an animated Dead Ringers.
Throw It In!: Jan Ravens ad-libbed what would become her Liz Truss impersonation's catchphrase of "I know!" since she felt even the show's cheerfully oblivious depiction of Truss wouldn't be able to believe she'd become Prime Minister.
