Mila Kunis admitted she could have a “good time” playing the erotic novel’s heroine Anastasia Steele.
The 29-year-old said: “There are times when you just want to do something fun and different, because you’re going to have a good time doing it.”
EL James’ book — which has sold 65 million copies — sees innocent Anastasia locked in an S&M relationship with kinky billionaire Christian Grey.
Harry Potter star Emma Watson, 22, has also been linked with the role. Drive hunk Ryan Gosling, 32, is tipped to play Mr Grey.