By MICHAEL GLYNN & RICK EGUSQUIZA

Stick-thin actress Ellen Pompeo has turned the set of Grey's Anatomy into a battlefield — and it's all due to her overinflated ego and insistence that she's the star of the show, sources say.

According to insiders, Ellen — who portrays Dr. Meredith Grey on the smash ABC drama — has outraged fellow cast members and show producers with diva-like behavior and demands for more money and preferential treatment.

"Just call her pompous Pompeo," said a show insider. "She's appointed herself the star of the series and has gone as far as to insist on separate interviews from the rest of the cast while on an overseas press junket." Ellen's arrogant attitude is getting on people's nerves, according to the insider.

"Ellen's become an insufferable jerk and her co-stars have really begun to resent her attitude and actions."

Tensions mounted during a recent cast trip to Monte Carlo, where Ellen reportedly insisted she be interviewed separately. Her publicist, Jennifer Allen, said it was producers who made the request "because she is the star of the show."

But that's not the way everyone recalls the situation.

"Ellen wanted to be interviewed alone, by herself," said a source close to the show.

"Grey's is an ensemble show, and there's no room for that kind of a star trip around here.

"Frankly, Patrick Dempsey is a much bigger star than Ellen ever will be. But even he doesn't have the same kind of ridiculously inflated ego she has."

Ellen also thinks her paycheck should be heftier than those of her cast mates, claims the source.

"I think she believes she should be getting the same kind of money that the Desperate Housewives stars make — in the $200,000-plus an episode range."

With Grey's move from Sunday to Thursday nights this fall — in an attempt to muscle out CBS' ratings smash CSI — insiders are saying that cast members are on edge about Ellen's antics.

"Ellen's turned the set into a war zone," maintained the insider.

"The show may be called Grey's Anatomy, but that doesn't mean the Grey character can't be replaced. The show is a success because of the interplay of the large cast, not one actor in particular."