I'm more relaxed about how the editing process will create a performance and that, in a way, gives me a sense of freedom.

The film depends on the audience's belief in this relationship.

I got to read some writings by serial killers, and they got inside my head. They were quite disturbing. I read disturbing stuff about that very detached way of manipulating people to do things.

I have grown up loving Shakespeare.

Performance is made in the editing room, and I've come to see the truth in that - the idea that they say performances are usually made in the editing room because what you film is the raw material. I think just going through the process of saying, "Which take do we use? Why is that the take we want? I want that take can you edit again, I'm not sure that's the one, I think it's this one." And just because you go through that process, I think somehow it's made me sort of more open about the [actor's] possibilities.

I admire the world of the books and the characters that she's created, but I'm not an addict of Harry Potter. I don't feel possessive about it.

I'm interested in the spirits of people. In the theatre, there's the acting part of acting - and I'm not saying that can't be great - and there's the essence. To explore that essence, you need a key, a look, a gesture, an insight that unlocks the person's soul.