The actress – who stars opposite Natalie Portman in the Darren Aronofsky – directed psychological thriller about a troubled ballet dancer – had to lose weight to become a typical dancer in the film, but was grateful to stop working out when it had wrapped.
She said: “To be able to pretend to be a ballerina for five months was great – but boy, was I happy to get out of that life.”
However the Hollywood beauty did enjoy the “challenge” of becoming so physically fit.
She said: “The best part was the challenge of it, the challenge of changing your body.”
Natalie – who won the Best Actress Oscar for the role earlier this year – worked out for eight hours a day to get as thin as she could to play a dancer.
Discussing it recently, she said: “You are constantly putting your body through extreme pain, so you get that understanding of the self-flagellation of a ballet dancer.”