Move over Thelma and Louise

'Have you seen the ring?' asks Mary McCormack, in her New Jersey twang.

Minnie Driver proffers her left hand to show an extremely tasteful sapphire engagement ring, a gift from her fianc?, actor Josh Brolin. The two actresses are sprawled across squishy seats in a high-rise hotel room in Los Angeles, supposedly for the purpose of discussing their new movie. But conversation has turned to the forthcoming wedding that will make Driver daughter-in-law to Barbra Streisand.

'I'm definitely a sapphire girl,' she says, 'although I didn't know I was until I got it. It turns out, as my mum just told me, that sapphires were all my gran wore.'

And did Brolin know that?

'God, no. It was a complete fluke.'

The 'Minnie and Mary Show' convulses with laughter. Female chemistry does not feature highly on the must-have list of Hollywood movie executives, but McCormack and Driver have bags of it. It's much in evidence in their new London-based chick flick, High Heels and Low Lifes, and they're clearly good mates off-screen, too. Maybe it's their rapport that has created the buzz surrounding the film. Advanced screenings of the screwball comedy - a sort of Thelma-and-Louise-meets-Lock-Stock - have moved even the most jaundiced film hacks to spontaneous applause.

Shot in and around the ever-groovier area of Clerkenwell (now so groovy, in fact, that it is being re-christened as the gloriously New York-esque 'Cityside') the film has Driver and McCormack as two cocktail-slurping party girls who attempt to blackmail a gang of crooks, headed by Michael Gambon. Thirty-one-year-old Driver plays a casualty nurse, a role that gives her the opportunity to sport a uniform designed by none other than Vivienne Westwood.

'I love it,' she laughs. 'She's going to be designing for the NHS any day, I'm sure. They'll close down a wing of the Middlesex so they can afford her. But really it was just artistic licence from the costume designer on the film, who was so French [puts on French accent]: "Why duz eet 'ave to be ugly?"'

Nurses seem to be a speciality of High Heels's director, comedian Mel Smith. In his debut behind the camera, 1989's The Tall Guy (another London-based comedy), it was Emma Thompson in the starchy pale blue and bonnet, playing opposite Jeff Goldblum. Since then, despite poor critical reaction in this country, Smith has made a fortune at international box-offices, directing Rowan Atkinson in his Bean film. His female stars were clearly impressed. 'As a comedy director, he just has it down,' says Driver. 'He's like an architect in that respect. He just has a good sense of what's funny.'

'It's sort of innately mathematical for him,' agrees McCormack. 'It's not his opinion - he's just right.'

For 32-year-old McCormack, a rising star who played shock-jock Howard Stern's wife in Private Parts, and will appear opposite Kevin Spacey in the forthcoming sci-fi drama K-Pax, it was also the fresh, unformulaic feel of High Heels that appealed. 'When I read the script I kept waiting for the love interest to happen,' she says, 'and it never happens. That was so great. Coming from the States it was unbelievable to me that someone had said yes to a female-driven comedy. Not even a girlie movie where we're supposed to learn lessons and talk about love and stuff. We're just making jokes.'

'And that doesn't happen in mainstream American films,' adds Driver, who lives in LA, 'because every studio note says, "Love interest, love interest, where is the love interest? Can't we turn this character into a man so he can be the love interest?" So that was part of it for me, too. And going back to England for the summer was a huge draw.'

Since she hit the big time in 1997, with her Oscar nomination for best supporting actress in Good Will Hunting, Driver has endeavoured to make at least one British film a year. Two of her better subsequent efforts ? The Governess and An Ideal Husband ? were made in the UK. For Americans, however, it is the outfit she wore at the Academy Awards ceremony - and being ditched by then boyfriend Matt Damon live on the Oprah Winfrey show ? that she is best known for. In LA at least, she will always be Minnie Driver, the Oscar fashion scene-stealer and famous dumpee.