Helena Bonham Carter

You don't look like the kind of actress who enjoys spending six hours in make-up every morning.

I thought it would be character-building. I haven't actually got attention deficit disorder, but I'm a bit of a moving target at the best of times. Luckily, it was an amazingly thin - what did they call it? - appliance. It was built up over the schnozzle, because monkeys have a muzzle. We had huge teeth to negotiate too.

How was it seeing yourself as an ape for the first time?

I loved seeing myself with a new face. That was partially why I did it. I thought, I'm bored with my face now, so it was great to inherit a new one. It's not every day someone asks you to be an ape.

You're not just any monkey, either. You're a monkey with a social conscience.

Yes, I'm a human-rights activist. Doing that while being dressed as a chimp is quite tricky. I actually got the hardest part. Even Tim Roth admitted it. He's a baddie, and he could be camp. I had to be earnest.

Mark Wahlberg is human; you're a chimp. Did you do any species intermingling?

I don't really know what I'm supposed to say about this. Am I supposed to perpetuate the mystery? Well, we do have a relationship, but it's quite uncategorisable. We don't actually have... um, it's a kids' film, let's put it that way. I don't know quite what we do. I won't until I see the finished film.

After acting in so many costume dramas, Fight Club must have been quite a change. Did it turn you into a boxing fan?

Not particularly. I've done a bit of aerobic boxing to keep fit, but I don't go and watch it. I suppose there's something very sexual about fighting. I don't mind wrestling. I wrestled with my brothers all the time when I was little. I never stood a chance.
And we had tickling matches.

Sounds like fun. A critic once wrote, 'Helena Bonham Carter makes intelligence erotic.' Do you know what that means?

When you said 'critic', I thought, 'Oh, no! Please don't.' But that's nice. I don't know what it means in relation to me, but personally I find intelligence very erotic.

• See more Helena Bonham Carter at Freeones (external link)