Keira Knightley and Michael Fassbender downed vodka shots before shooting scenes for 'A Dangerous Method'.

It was a vodka shot to calm our nerves and away you go really

The pair star as Sabina Spielrein and her therapist Carl Jung in the David Cronenberg movie and Keira, 26, admitted they got through the more uncomfortable scenes - which include Michael spanking her - by turning to alcohol.

Keira told Culture magazine: "We only had one or two shots maximum. It was a vodka shot to calm our nerves and away you go really. Then we had champagne. We drank quite a lot of champagne actually. You can count on Michael to buy a bottle of champagne when one is required. The vodka and champagne is a good combination."

Keira also revealed she now only chooses roles that challenge her and she loves to be frightened by her movies.

She added: "I think all the work I have done over the past five years has looked for the thing that really frightens me - the thing that I really don't know how to do. I think it is for selfish reasons. If you manage to do something that is a big challenge, you get a hell of a lot out of it, regardless of whether the end product works or not."