Knightley plays psychiatric patient Sabina Spielrein in David Croneberg’s new movie about Sigmund Freud and the birth of psycholanalysis, in which she has a vaiety of sexy scenes, including getting spanked with a cane by Michael Fassbender’s Carl Jung.

For scenes in which her character enjoyed a little ‘personal pleasure’, Knightley practiced a variety of faces in front of the mirror and then showed Cronenberg over Skype for his thoughts and suggestions.

She says: “It was a huge part of what Sabina was doing a lot of the time. So I asked psychoanalysts about it and they said, ‘Sex and anything like that is trying to release energy, trying to release pent-up emotion’.

“So I worked with that and sat in my bathroom and pulled faces at myself for about two days, trying to figure out what it was going to be.

“Then I got on Skype with David and went, ‘I’ve come up with this’, or, ‘I’ve come up with this’, and he went, ‘That one!'”

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Knightley has also revealed that she had to have a couple of vodka shots in order to relax for some of the movie’s steamier moments, including the aforementioned spanking scene which they toasted completing with a glass of champagne.

It’s a tough job being an actress, by the sounds of it.

Photo: 2009 Lions Gate Films Inc.