(CNN) Tilda Swinton has undergone more on-screen transformations than perhaps any actor of her generation -- but the Oscar winner's latest stunt has still managed to catch Hollywood by surprise.

Swinton has laid to rest months of internet speculation by reluctantly revealing that she is in fact the 82-year-old male actor Lutz Ebersdorf -- who was previously credited as playing Dr. Josef Klemperer in the upcoming movie "Suspiria."

Four hours of makeup was required every day to turn Swinton into an octogenarian man, the actress told The New York Times

Her commitment to the role went above and beyond -- with Swinton even insisting on having fake genitalia made and attached, according to the movie's makeup artist, Mark Coulier.

Swinton also plays Madame Blanc in the remake of the 1977 Italian horror flick, released later in October, but her revelation puts an end to a long mystery surrounding Klemperer's role.

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