Emilia Fox: Weird rituals at the theatre

What was it like working with Roman Polanski?

Extraordinary, especially when it was my first big screen movie. Even though he's in his sixties now, he's got the energy of a 14-year-old – running around, moving everything himself. And what he gives, he demands, so you really want to please him. You end up feeling a bit like a child because you want to get it right for him. I remember him telling me to look up into Adrian [Brodie]'s eyes [heavy Polish accent] "like you're a Grrroupie! Imagine he's a Rock Starrr and you're his biggest fan" And I was like "I know exactly what you mean. And I will do anything for you. And shall I jump off this cliff now? OK!"

In one scene, you play the cello very convincingly

I was really playing – I have learnt the cello since I was four, and I nearly became a professional cellist, although I am now a bit rusty. But playing for Roman was nerve-racking, especially because he decided to operate the camera for that scene.

How do you approach auditions?

I always go slightly dressed as the character if I can. With a little twist of humour on to the character. Once, the character was this very cold, nasty Nazi. So I went in wearing this slightly military jacket and straight trousers. Of course, I didn't get the part, so I probably should have gone in a little dress with fairy wings on ...

Are you in a relationship?

I am. A happy one, yes. He's called Julian. No, he's not an actor. There is a 10-year age gap, but I've never really had a problem with that – maybe because I was basically an only child, and I've always been surrounded by older people. He's done things that I have yet to do, which is rather wonderful.

Is your family always talking about acting? Do you discuss camera angles over the cornflakes?

Never. Never. Everyone sticks to their own corners. Mum and Dad wanted me to find my own feet, and we still don't talk about work much. I mean, you wouldn't talk about the office at home. We don't even watch each other's work. Dad came to see The Pianist last night, which was an absolute miracle. We don't really follow each other's careers. Secretly we all love doing it, but when we're at home we all play it very cool: "oh, not working, no, too many letters to write ..."

Your uncle the actor James Fox is a committed Christian – does he ever try to convert you?

I've never had any connection with his religion at all. But it's obviously really helped him in his life, which is a wonderful thing. But nothing is pushed on to us. He's not ringing my doorbell with a pamphlet, no.

Are you superstitious?

Yes. I'm terrible. For one magpie, I do "Morning Mr Magpie, Hope your Family's Well" [with movements]. And in the theatre I have very weird rituals where I have to touch every piece of wood on the way to the stage, and if I miss one I have to turn around three times. It's crazy. Crossing people on the stairs, you have to say "white rabbits"; and if an ambulance passes, you have to touch something white. God, I collect them. But I'm not as bad as an Italian director I worked with who wouldn't even let anyone on set if they were wearing purple or green.

What makes you happy?

Finding a great book that you don't want to put down. Being in Dorset, at my parents' house by the coast. Waking up and looking forward to the day. I do do that, do you? I am quite a morning person. I love nothing better than waking up on a work day, at five am and thinking "oh yes I'm going into work". That's a nice job, isn't it!

Do you go out much?

I'm pathetically bad at it. I'd love to get dressed up and go dancing but it's exhausting when you can't hear to talk to people. To tell the truth I find clubbing boring. I love staying at home and being cosy.

Do you miss having blonde hair?

No; being blonde you attract all these weirdos and people winking at you. Now I'm dark, people don't bat an eyelid. And as an actress, you're allowed into far more parts.

Do you have vivid dreams?

I dream about being chased by spiders a lot. I don't know if they symbolise my worries coming running after me, or whether it's just pure terror of spiders. If I see one coming I literally get into a paralysis of fear – Julian laughs at me – but I start to hyperventilate and I burst into tears. It's pathetic. I'm sure Freud would have something extraordinary to say about it. He'd say it was sexual, but

I can't imagine my spider is someone sexual chasing me. If it is, it's someone I really don't want to be with.

What do you make of fame so far?

I think problems come – and I have seen it with a lot of people – when they start believing their own hype. I mean for God's sake, they're just an actor. It's not brain surgery, it's providing escapism for people on a Saturday night. Of course, you feel wonderful being asked to wear someone's clothes – you know, a designer's – and having cars pick you up. It is like a treat, like a fairytale. But you'd better expect fame not to be there next month, and learn how to drive and go on the tube.

The Pianist is on general release