Though it’s war at the box office as her new movie “Charlie Wilson’s War” battles other holiday fare, Julia Roberts’ mega-watt smile says it all: After taking a break from Hollywood, she’s at peace in her life as a wife and mother of three.

Julia was four months pregnant while shooting her famed bikini scene in the war drama, but she admits she was nervous about breaking the news to her director Mike Nichols and his wife Diane Sawyer.

“The day before we shot that scene, Mike Nichols and Diane, his wife, had come to our house for lunch,” she explains. “They're great friends of mine and Danny’s, and Danny said, ‘Should we tell them our exciting news today?” That's a great idea, but really in the back of my mind I was thinking, ‘Hopefully Mike won't make me put on that bathing suit!”

Besides baring all, there was a lot of kissy-face and butt-grabbing between Julia and Tom Hanks in the film.

So who had the better butt?

“I think we’re pretty on par,” she jokes.