You have to play the logic of a character.

During Breaking The Waves, I was on my own in a hotel room. I think I would have been impossible to live with. When you go home, you have to pretend to be the person you are at home.

As actors, we went where we wanted to, and the camera followed us: it was like having another person in the room. There was no formal structure to the process. It was very liberating.

You have to play the logic of a character.

And it is very sexy as well: somebody says I'm taking you on a surprise date, you don't know where you are going and you can't see and then you put your hand out and there is a tiger. Amazing.

My character Lena is somebody who responds to people in a very simple way. I didn't have to take myself off to a darkened room to concentrate, I just had to try and be open. It's an interesting, subtle relationship.

It's a whole different kind of anxiety. But the great thing about doing a theatre job is that once the ball starts rolling you just have to go with it, it's inexorable.