Tilda Swinton donned a prosthetic penis to play an 82-year-old man is 'Susperia'.
The 57-year-old actress portrays Madame Blanc, the head of a dance company, in the horror movie, but she also played psychoanalyst Dr. Josef Klemperer under the alias Lutz Ebersdorf, but she and director Luca Guadagnino kept her male persona a secret while filming.
Tilda said: "The intention was never to fool anybody. The genius of [make-up artist] Marc Coulier notwithstanding, it was always our design that there would be something unresolved about the identity of the performance of Klemperer."
Marc created some "weighty" prosthetics to help Tilda feel more manly, as well as thickening her neck and building her jaw out to look more masculine in a process that took four hours a day.
He said: "Although she has a slightly androgynous look from sort of a fashion-model point of view, Tilda's got a very feminine bone structure...
"She did have us make a penis and b***s. She had this nice, weighty set of genitalia so that she could feel it dangling between her legs, and she managed to get it out on set on a couple of occasions."
But the make-up artist has no idea what happened to the fake genitalia.
He said: "[It is] probably in a box somewhere! I should try and find it, and put it on a plaque on the wall of my workshop."
Tilda insisted on being called Lutz on the set, and many of the extras and crew had no idea the Oscar-winning actress was hiding under heavy make-up.
Mark said "They were all like, 'Is this a famous actor, Lutz Ebersdorf?' They'd go on IMDb looking for him, and there wasn't any information."
Paparazzi photos released almost two years ago first sparked speculation that Tilda - who eventually created an IMDB page for her alter ego - was Lutz and she admitted it wasn't something she had wanted to be revealed at all.
She told the New York Times newspaper: "Frankly, my long-held dream was that we would never have addressed this question at all.
"My original idea was that Lutz would die during the edit, and his 'In Memoriam' be the final credit in the film."
Director Luca insisted in February that claims the actress was also the lead male actor in the movie was "fake news", while at the premiere at the Venice Film Festival last month, Tilda read out a letter that was attributed to the reclusive Lutz to explain his absence.
The note explained the first-time actor was a retired psychoanalyst living in Berlin and explained he was a "private person" and "strongly suspects" 'Suspiria' will be his only movie appearance.
tagged in Tilda Swinton