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." ------------------- Read more:
------------------- 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."