MTV is getting ready for the Sunday's Movie Awards -- and part of that preparation is preventing a full-on catfight between Cameron Diaz and Jessica Biel on live TV. (If you recall, Cam "blew up" when she saw her ex, Justin Timberlake, flirtin' it up with his now-GF Jessica Biel at a Golden Globes after-party in January.)

"Everyone is determined to keep Cam and Jess far apart," an insider tells Page Six. Both girls are set to present awards, and Cam is nominated for Best Kiss with Jude Law for The Holiday. "Jessica is definitely not presenting that one," the insider reports.

Then comes the problem of arrivals: The biggest stars always walk the red carpet last, and perennial A-lister Cam wants to avoid the "humiliation" of arriving earlier than new It Girl Jess. "It's becoming a big deal because the girls both want very separate arrival times," the insider says. "Cam is used to being more high-profile than Jessica. But now that Jessica's dating Justin, she has more leverage. Cameron's looking a little unstable lately."

And, like a truly scorned ex, Cam is planning her entrance based on Jess'. "Nobody knows who Cameron is going to bring, if anyone," the source says. "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."

Sure, it's a mess for MTV, but any slip-up on their part could make it an interesting show for the rest of us!