Natalie Portman couldn't play a serial killer.

The 42-year-old actress - who won an Oscar for her outstanding performance in now-husband Darren Aronofsky's psychological horror 'Black Swan' - tries her best not to take her work home with her.

She told Radio Times magazine: "I don't do things that are painful. I can't starve myself for a role;

I can't cause myself pain. I'm the opposite of that. I get acupuncture, I go swimming. I like to cook. I like hanging out with my friends! When I'm not working, I need those days where I just stare at the wall for a few hours and refresh by doing absolutely nothing. I can relax, but when I work, I want to do the best job."

The 'May December' star also has no time for anyone being "unkind" on a film set.

She continued: "There's a discipline to being a good person while you're working.

"If there's someone being unkind on set, it takes me out of my focus. I have no patience for that.

So that's part of the discipline, too. Being kind and kind.

To see directors who do that - because there is a great deal of stress - is remarkable."

Asked if she would ever consider method acting, where the actor emphasises on a deeply emotional level with the characters they are playing, Natalie replied: "If you did, I don't understand how you would play a serial killer!

"It's inevitable you'd take something home with you ... that's not even a choice.

"That's why you have to be careful about what kind of roles you choose, because it affects you definitely, but I just don't really understand the idea of becoming your character.

"That would get rid of half the characters you could play, because it would be illegal!"