Queen Zee: happy as a lark-in

She's not sure which she enjoyed most - working with Soderbergh or being pregnant. 'It was so liberating to do this kind of film because of the way Steven shot it. It's hand-held cameras, guerrilla film-making and faster than hell. I didn't have time to sit down or get tired. I loved working like that. And I felt so great. I had so much energy when I was pregnant. I had these pre-natal vitamin pills that just kicked in big-time and I never felt better. I was telling people I felt like I could be pregnant for years.'

While they probably don't use words such as 'helmed' in Wales, Zeta-Jones still sounds like she's just tramped across a Welsh valley. And unusually, she gets to speak with her own voice in the film. Playing a wealthy socialite living in Southern California, Zeta-Jones at first felt uncomfortable.

'I said to Steven, "Do you want me American or Hispanic?" And he said, "No, just the way you speak." I said, "What? Welsh with a bit of English and American thrown in?" At first I felt so aware of my voice because even when I was doing theatre in Britain, I had to hide my accent. And the thing is I love doing accents. I'm getting like Meryl Streep. Just give me an accent any day. Because you really do cover yourself with the way you speak. And that's one of the great things about America. Everybody is from somewhere else, and everybody fits in. Coming from Britain, the way you speak dictates where you were bred and how you were educated. That doesn't happen in the States, and I love that it doesn't.'

In the film Zeta-Jones lives a charmed life, one which is almost ripped apart when she discovers her husband is a drug dealer. Did she meet wives who had experienced similar scenarios?

'No, because I really wanted this to be as if it was really happening. And I think I would be exactly as I am in the film. I actually do know someone whose husband was involved in certain things she knew nothing about. I know people whose husbands were having an affair and they've never ever found out. And of course, you think, "How could you not know?" I know someone who found out her husband had a whole other life with family and children on the other side of the country. But life is unpredictable.'

Indeed it is, and few could have predicted Zeta-Jones's swift ascent to film critics' darling. Even better in her mind, the Traffic role has radically changed the perception of Zeta-Jones in Hollywood.

'Yeah, that Entrapment leotard just ain't going to work any more,' she laughs, seemingly thrilled. 'Everyone gets pigeon-holed, especially if you're successful in one genre of films. Everyone bombards you with the same old thing, you know. They want you to do that thing because they know it sells. And to some people, I'm still Mariette Larkin from The Darling Buds Of May. That's how long it can take to get out of the mould. But I know the perception of me has changed and I couldn't be happier. When it's about something other than how you look in a frock, that gives you a wonderful sense of commitment to what you do.'

There's something particularly intriguing about Zeta-Jones being fascinated with the film's gritty realism - gritty realism not having played much of a part in her public media life of late. What would she like people to take from Traffic?

'A sense that this is a problem going on in every social strata. It's not happening in the mean streets of the ghetto. It's happening to your children around you. I hope that's what people will take from it. And they should really look closely at Michael's story in the film. It's really devastating.'

Michael is, of course, Michael Douglas. But before cringeing at the prospect of the pair cosying up together on camera, think again. The newly-weds are smarter than the cynics think. 'Our paths never cross in the movie. It's almost like three movies at once. Three stories which are subtly intertwined. So it puts us up there but separates us. We didn't want this to be the Catherine Zeta-Jones & Michael Douglas Show. We don't want to kiss on screen, for example, and have people have preconceptions and find it all voyeuristic. I'm the first person to put my hand up to complain when you're watching real couples on screen. When you watch them it's almost like you're spying on them. But we were just blown away by the fact that we could both be actors in this great piece of work.'

Given the film's subject matter, what would Zeta-Jones's legal drug of choice be? 'That would have to be Cristal champagne and a good shop.' She ponders her answer for a moment. 'Hmm, but I have to say, I'm not enjoying shopping like I used to. I used to love it but I went out the other day and came home with nothing. My husband was very impressed.'