Spin Cycle

ON THE HOT SEAT Julia Roberts on July 10's Late Show With David Letterman -- her first public appearance since her sudden split with Benjamin Bratt. THE TASK Prove she's America's Sweetheart, not a Runaway Bride. CHOICE OF FORUM Dave and Julia's mutual admiration has been gushingly documented -- on this occasion, he dubbed her ''the biggest star in the world.'' THE PERFORMANCE Clad in a flowing pale pink blouse and pants, the Pretty Woman was radiant -- and plucky about the inevitable question, telling Dave ''We all know what you're up to.'' By asking the audience whether they wanted to hear about the split, the Oscar winner gamely sated our tabloid curiosity but remained in complete control of the information. While shooting down the rumors that her Ocean's 11 costar George Clooney was to blame for the Bratt sack, she earned points for classy sound bite: ''He's a good man, he's a fine man. He is, to the exultation of the female single population, not my man anymore.'' Not only did Roberts make her case, but she gained extra sympathy by zinging the press: ''My only regret is...the media can't accept that [the end] was tenderhearted and kind.'' OUR GRADE Another Oscar winner: A