It's just as well she works out then, bearing in mind she doesn't have much time to get in shape before filming starts for her next role - as a ballerina in The Adjustment Bureau, alongside Matt Damon. "I saw my trainer yesterday, so I'm feeling worse for wear today," she says dramatically. "I'm going to dance boot camp.
I'll never be at the same standard as a professional, but hopefully I'll be able to do a little bit. I didn't do ballet when I was a child; I gave it up when I was three - in some sort of bratty rage, claiming it hurt my feet."