The 42-year-old, who is married to screen legend Michael Douglas, says she loved getting the opportunity to start dancing again for her role in a musical, but admits she is lazy to exercise often.
"I haven't danced for a while. I work out and I have a ballet barre in my gym. But every time I do it I think, 'Why don't I do this all the time?'," a website quoted her as saying.
"I get lazy so working on this film was a bit of a shock to the system. It was like 'OK, I remember those Achilles, I remember those thigh muscles'. All those elements came back and it worked out great," she said.