http://nz.entertainment.yahoo.com//070529/6/jpu.html

Diaz and Biel set for showdown

Photo : SPLASH

Diaz and Biel are lined up as presenters at next month's MTV Movie Awards.

And Diaz's ex Justin Timberlake - now dating Biel - is set to get an award for his role in Alpha Dog.

Now insiders are trying to keep the women apart, after they had a dust-up at a previous awards ceremony.

An insider told the New York Post: "Everyone is determined to keep Cam and Jess far apart.

"It's becoming a big deal because the girls both want very separate arrival times.

"Nobody knows who Cameron is going to bring, if anyone. But if Jessica walks with Justin, Cameron will want to bring a date. If Jessica goes alone, Cam will probably walk alone. It's a mess."

Diaz reportedly "blew up" at her then-recent ex when she spotted him flirting with actress Biel, 25, at an after-party at the Beverly Hills Hotel in January.

The biggest stars are usually the last to walk the carpet - a position both women hope to land.

Diaz, 34, who is accustomed to being at the top of the A-list, wants to avoid the "humiliation" of having an earlier arrival time than Biel at the MTV event.

"Cam is used to being more high-profile than Jessica," said the source. "But now that Jessica's dating Justin, she has more leverage. Cameron's looking a little unstable lately."

The ceremony is also being carefully crafted to avoid a run-in because Diaz was nominated in the best-kiss category for her lip lock with Jude Law in The Holiday.

"Jessica is definitely not presenting that one," the source said.

A spokesman for Timberlake, 26, did not return calls.

The MTV Movie Awards takes place in Los Angeles on June 3.