Enjoy Julia Roberts while you can this December in the adultery drama ''Closer'' and the heist sequel ''Ocean's Twelve.'' After that, you may not be seeing her for a while. She tells Newsweek that, after she becomes a mom this winter, she has no plans to return to movies. ''It's a whole new life!,'' says the 36-year-old actress, who's expecting fraternal twins by husband Danny Moder. ''I'm not planning anything. I can't imagine how big I'm going to get in the next three months, but hell, you just kind of play it as it comes. I'm allowed to do that, aren't I?'' While Roberts won't say how long a maternity leave she's anticipating, maybe ''Closer'' director Mike Nichols could eventually coax her back to work. As she told EW earlier this summer, ''Like a devoted puppy, I will follow that man to the ends of the earth.''