Actors becoming romantically involved while making a film together is almost an occupational hazard in Hollywood - but sometimes it's a match made in publicity heaven.

Petite blonde livewire Brittany Murphy and gangly Ashton Kutcher are Hollywood's lovebirds of the moment, and it has done wonders for their new romantic comedy, Just Married.

Defying the critics, the screwball farce about a young American couple's disastrous honeymoon in Italy has done well at the American box office, helped enormously by the couple's real-life love affair.

The two wore matching silver rings at the Hollywood premiere in January and, on the publicity circuit recently, they have been confessing how they fell in love while making the film.

In the movie Murphy plays a well-to-do girl who falls for an unsophisticated guy (portrayed by Kutcher), which leads to a honeymoon from hell as the newlyweds are constantly frustrated in their attempts at love-making.

But their relationship is blossoming off-screen, Murphy admits: "It's definitely a real life romance at this point. I fear we're tampering with the film gods in more ways in our private lives than I'd wish to divulge."

The film's director, Shawn Levy, says sparks flew early on between the two young actors on the set. "The chemistry between them was wildly self-evident the first time they were together. It was very clear there was some special dynamic going on."

They have been an item for about six months, ending speculation that Murphy and rap star Eminem had a fling during the making of 8 Mile earlier last year.

A tiny 5ft 1in ball of energy, Murphy has been garnering increasing attention after acclaimed performances in Girl Interrupted and Riding In Cars With Boys.

Just Married allows Murphy to show off her comic timing after a series of emotionally-charged roles, and she welcomed the chance to be funny again. Her breakthrough film role was in Alicia Silverstone's 1995 hit comedy Clueless.

"I loved the chance to do Just Married because it takes me back to my roots - I started out in comedy," she says. "I'm trying to do a little bit of everything."

Born Sharon Murphy in Atlanta, she was raised in New Jersey. By the time she was 13 she'd convinced her mother to move to Los Angeles so she could chase an acting career.

This led to television commercials and sitcoms (Drexell's Class) before her breakthrough film role in Clueless.

"The simple things like having a wonderful mom and health and happiness make me feel comfortable inside and give me a sense of security."

She maintains she never planned on Hollywood stardom: "I just wanted to entertain, there wasn't really a vision of all of this." she says.

"This is basically about wanting to get out all that's inside of me," she says about acting.

"I've always been an emotionally hyper sort of person and now I'm getting paid for it."

Plans for Murphy to depict wild-living 60s rock singer Janis Joplin in a biopic have been put on the backburner because of problems with the music rights. Next up she'll play a drug-addicted stripper in Spun.

Happy playing wildly different characters, Murphy muses: "There's probably 200 people in me. They look like me and it's kind of like a ghost thing. I love changing the way I look."