If I don't do this film. I'll be acting in corsets for the next 20 years.

I worked with John Maybury on The Jacket and I think he's an extraordinary film-maker. I read the first drafts of this piece when I was working on The Jacket, and we'd so fallen in love with him that we thought he was the only person that should direct this! We wrote poems for him, we sent him champagne and cakes. Four years later he finally read it.

You live with a writer [a mother], and you grow up with their words, their kind of fantasies, and I'd pretty much seen every single one of her plays, and been in a lot of rehearsal rooms, so it felt very natural and easy. It was lovely to get an opportunity to do that professionally as well.

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.

The thing I love about acting is getting to change and look at different people in different lives and do different projects.

I went through voice coaching. I was absolutely terrified. I thought my knees were going to buckle, and the first couple of takes I sounded like a pubescent boy. I didn't realise I was going to have to do it live.

I don't read my reviews. Unless I'm unfortunate enough to catch something by accident, which happens, and it's always a bad review. Always, it's amazing. I will be sitting in a café, and I will open a random paper right to the page of the review.... And then you're sucked in and go home and never want to go out again.