People have lots of misconceptions about me. My mum, who is half French and half Spanish, gets outraged when I'm called quintessentially English. I owe my looks to my mum-which was 90 percent of getting my first job. And, some people would argue, 90 percent of my entire career.

I enjoy those small chats you have when people come up and talk to you about your work. It only involves a few seconds of effort to be nice to those people, and I am very grateful for the kind words that people have taken the trouble to express to me in person.

I just thought I‘d never look good in what everybody else wore. So there’s no point trying. You just have to do what suits you, and it doesn’t matter if you don’t look like everybody else. Be you. That’s our gift and we’ve got to celebrate that, but it does take ages. I was wracked with self-doubt for years. I get spasms of it even now – I’m not indelibly self-confident.

J.K. Rowling said Bellatrix's role was going to be significant in the last one, when I showed some reluctance in playing a tiny bit part. Up front, they said, 'You're very significant in the last one.' But significant could mean a lot of things. That could just mean a significant plot point. Doesn't necessarily equal big part.

Wear what you feel comfortable with. People say nasty things about what I wear in the street. I'm always in worst dressed lists, but you just have to dress for yourself and ­nobody else.

Fairytales have always got to have that scary quality, as long as you make them laugh.

When you're up for an Oscar, you just get offered everything. It's fantastic, but a lot of it you're completely inappropriate for.