Catherine Zeta Jones better make sure she steers close film pal Julia Roberts well out of range of any sharp objects. The Pretty Woman star is apparently furious that Zeta Jones has been given top billing on the posters for the forthcoming Ocean's Twelve.

Roberts, Hollywood's best known female star, has been away from the spotlight over the last couple of years, given her lack of large summer releases and blockbusters, only to be occasionally glimpsed in forgettable films such as Mona Lisa Smile, and a cameo in the George Clooney-directed Confessions Of A Dangerous Mind. In fact, her last two successes have been Ocean's Eleven and America's Sweethearts, where she and Zeta Jones played siblings.

In a ruthless industry infamous for its short memory span, it is vital for a star to protect her image constantly. Julia's glamourgirl status has been further affected by her marriage and current pregnancy with twins, which restrict both her cinematic as well as her social and media commitments.

At the same time, Catherine has been firmly cementing her place in Hollywood, and even getting herself one of those Acadamy Award statuettes for her performance in Chicago.

Julia played Tess Ocean in the 2001 remake of Ocean's Eleven, and this time the sequel finds its new number with the addition of Catherine Zeta Jones, playing Brad Pitt's love interest, Isabel Lahiri.

Expecting twins in January, Julia was shocked to see Catherine taking a plum fourth place on the poster after George Clooney, Brad Pitt and Matt Damon, while she herself wallowed at the bottom, underneath Andy Garcia, Don Cheadle and Bernie Mac.

IMDb.com reported a film source as saying: 'Julia's not happy. She was in the original Ocean's film -- Catherine wasn't -- and she assumed her name would be first. It might sound petty, but being top means a lot in Hollywood. It means you are the biggest star. Julia and Catherine get on well on a personal level -- but this is business.'

Director Steven Soderbergh can either grin at the publicity this just-beginning catfight is affording his Ocean's Twelve, or he can worry about the friction actually escalating enough to disastrously affect his all-important press junkets, which should be getting under way very soon for the December release. 

With the ladies taking their gloves off, perhaps this might just spark off a battle of top-billing interests among the leading men. Picturing Pitt and Matt Damon taking on Soderbergh-favourite Clooney sounds more fun than a probable Ocean's Thirteen, and could even form the core of Trey Parker and Matt Stone's next film!