Keira Knightley had to drink vodka to pluck up the courage to shoot her spanking scene in A Dangerous Method.
The 26-year-old actress was worried about the racy sequence from the first time she read the script, and admitted she needed to have a stiff drink before filming started and admits she is not keen to repeat them.
Speaking at the Toronto Film Festival, she said: "I did a couple of shots of vodka - definitely - beforehand, and then a couple of glasses of champagne as a celebration of never having to do that again."
The film - made by controversial director David Cronenburg - is an examination of the relationship between psychoanalysts Carl Jung and Sigmund Freud - played by Michael Fassbender and Viggo Mortensen respectively - and Keira plays Sabina Spielrein, a Russian who has an affair with Carl.
Keira was so nervous about the erotic scene, she even threatened Michael beforehand.
She revealed: "I did actually say to Michael before one of the scenes, 'I've got a security guard outside. You touch me and he's gonna break your legs!'
"And he was like, 'Keira, you're tied to a bed. You're not really in a position to say that.'"
For the actual scenes, Michael ended up spanking a box placed next to her. Keira was initially so wary of her spanking scenes she wasn't sure she could take the role.
She told The Hollywood Reporter: "When I first read the script, I thought, 'The script is fascinating, and it's David, and I really want to work with David, but I read those two scenes and just went, 'I don't think that I can do that,' particularly because it's the age of the Internet; it's gonna be everywhere; I don't want that out there.' "
She was, however, reassured when he told her the scenes wouldn't be "voyeuristic" or too sexy.
She added: "I said to him, 'Look, I love you, I love the script, I love the character, but I really don't know that I can play those scenes.'
"He said, 'Look, if I'm gonna do them, then they're gonna be clinical; they're not gonna be sexy, they're not gonna be voyeuristic in that way.'
"And I thought, 'OK, well I can understand that. As long as it's clinical and it's not some, sort of, weird sexy spanking thing.' "
- BANG! Showbiz