The set of Grey's Anatomy is about to get a lot more chilled out. Katherine Heigl is taking a leave of absence from the hit show for five weeks to shoot a movie and there are some in the cast and crew who are happy to see her go.

Katherine will begin filming the romantic comedy Life As We Know It this month, and an insider tells BettyConfidential that certain cast members are "ecstatic" that she will be gone for more than a month.

"To say they're breathing a sigh of relief is a nice way to put it," the insider says. "They even hope that filming on the set of her movie is delayed so she misses more time."

It seems Katherine, who has a reputation for shooting off her mouth, has been rubbing people the wrong way since filming began on season six of Grey's Anatomy.

"Because her last film The Ugly Truth was such a big hit and she's expecting her upcoming film, Five Killers [with Ashton Kutcher], to be just as big, she's been rattling cages," says an insider.

The source tells BettyConfidential that after her best friend T.R. Knight left the show last season, "Katherine's co-stars expected her to be humbler and easier to deal with, but instead she began complaining from the start."

Back in July, she moaned to David Letterman about having to work super-long hours on the set. "Our first day back was Wednesday and it was - I'm going to keep saying this because I hope it embarrasses them - a 17-hour day, which I think is cruel and mean." What she didn't reveal was that the extended hours were scheduled to accommodate Katherine, so that she could take time off to promote a film.

When Letterman asked her how much longer she was going to be on the show, Katherine replied, "Yeah, that's what I keep wondering."