The words "identity theft" seldom inspire comfort when forming the basis for a film pitch. The end result generally involves an unwitting everyman plunged into a conspiracy theorist's nightmare, trying to prove they are who they say they are as a sinister puppet master connives to steal their life/erase all evidence of their existence.

Not normally the ingredients of a romantic comedy then. Yet it is a bit of maliciously intentioned computer hackery that lies at the heart of The Accidental Husband, a new millennium take on the old screwball comedies of the 30s.

Uma Thurman stars as Emma, a radio love doctor whose advice to a listener results in her ending her relationship.

The listener's spurned boyfriend then seeks to upset Emma's perfectly organised love life by altering computer records to make it look as though he is married to her, then feigning ignorance when she tries to find out how the mix-up has happened.

The comedy comes from the gradually unbuttoning of Emma as she warms to the spontaneous nature of her "husband", who turns out to be a rough and ready New York fireman.

Jeffrey Dean Morgan, the Mr Dependability of American television (he played the dead husband in Weeds, the demon hunting father in Supernatural and charming heart-transplant patient Denny in Grey's Anatomy) is the secretly scheming spouse.

Colin Firth finds himself in the rather more thankless role of Emma's real fiance, a rather staid and conventional publisher.

It is the type of vehicle that could have been made for Meg Ryan and Sandra Bullock at their comedic peak and more latterly Reece Witherspoon or Renee Zellwéger.

Unfortunately for the writers, it was Uma who came across the project a decade ago and decided she wanted to get it made.

"Ten years ago I was in old period dramas, dressed up in corsets. Some of them were good but I always wanted to do what I wasn't being asked to do.

"I couldn't get arrested to play in any contemporary comedy in America which frustrated me no end. When I found this piece of material from two young writers who are both based in London, Mimi Hare and Clare Naylor, I thought this was a good character here, a great idea and a great title. I thought I'd just do it myself, I'll cast myself. "

The result is a something of a vanity project for 37-year-old Uma the producer as she tries to show off her versatility and a flair for slapstick schtick which, to be brutally honest, she just doesn't have.

"I felt bad for them (Mimi and Clare) that their best champion was me," she says honestly. "No wonder it went slowly, people weren't knocking each other over to put me in a romantic comedy."

Colin Firth was a safe pair of hands to play an emotionally closeted Englishman having essayed similar characters on numerous occasions in Love, Actually through two Bridget Joneses to the more recent St Trinians.

Though he might have created the ultimate romantic icon of Mr Darcy, the smouldering in this movie was left strictly to the NYFD.

"The quintessential Englishman does exist very strongly in a lot of women's minds," says Uma. "Everyone's waiting for their quintessential Englishman to land upon them. But the appeal of firemen is that they're courageous, often handsome, fit, brave. Really, it's right out of Lancelot."

Mother of two Uma did identify with her character's sensible attitude, to the extent that it is a convincing front for her real self which, she says, is a little more, well, in keeping with her hair colour.

"The reality is I am probably more like the impulsive Emma, but I've pretended to be pragmatic for most of my life. I put on a pretty good pragmatic show.

"I would love any back-up career (like hers) though, that I could do without having to go into make up and hair. I could age gracefully behind a microphone. I actually enjoyed doing that."

From her career-making turn as the mob-boss's wife with the unfortunate narcotics habit in Pulp Fiction to the sword wielding assassin of Kill Bill, Uma has played to her strengths when portraying femme fatales who are vulnerable on the inside.

To be honest, on the basis of reviews for Accidental Husband, it seems many critics would prefer she stuck to what she does best, which is kicking ass and taking names.

"You know, I should make another female action-hero type of film but I haven't found the script for it, that demanded I go through all that exercise."

But then as she herself admits she is about as successful at taking advice as radio doc Emma is at giving it.

"When I told my mother at the age of 12 that I wanted to be an actor she said 'What, are you kidding? Everyone wants to be that, don't be ridiculous'.

"It was a good piece of advice. I didn't take it."