It's a tricky one when you're playing somebody who is mad. There's often the big actor's question, if you're playing a part like that: do you take it to be an internalized thing, pull the audience in, or do you go full-out, and kind of present it as quite a shocking thing?

In film as a medium, you're often given a baddie and a goodie and told what to think about them; it's usually a very definite point of view.

Half of my mum's family is Welsh. I remember when I was a kid she used to read to me, and witches and wizards in books always had a Welsh accent, so I guess I took it from that really.

Well, the thing about great fictional characters from literature, and the reason that they're constantly turned into characters in movies, is that they completely speak to what makes people human.

I've got a lot of experience with anorexia - my grandmother and great-grandmother suffered from it, and I had a lot of friends at school who suffered from it. I know it's not something to be taken lightly and I don't.

I do think that acting is such an unpredictable job, and you're away a lot. If you're dating somebody outside the industry, it can be hard to understand that.

Bigger films are more difficult because the number of people is so huge.