Gwen Harrison (CATHERINE ZETA-JONES) and Eddie Thomas (JOHN CUSACK) are a married, Hollywood couple known as "America's sweethearts" and have appeared in numerous popular films together. Unfortunately, they're headed for divorce due to the pampered and self-centered Gwen having an affair with a Spanish actor, Hector (HANK AZARIA), some eighteen months ago, sending Eddie off to a "wellness center" where he's been trying to cope ever since.
That's not good news for studio chief Dave Kingman (STANLEY TUCCI) since the two have fallen out of public favor, putting their last and yet to be released film together, "Time Over Time" in jeopardy. Knowing he needs America to believe that the two former sweethearts are back together for the picture to be a hit, Kingman asks movie PR veteran Lee Phillips (BILLY CRYSTAL) to arrange the press junket for the film.
Lee is understandably reluctant since Kingman just fired him the week before in favor of his younger protégé, Danny Wax (SETH GREEN), and the fact that the film's Oscar winning, but seemingly deranged director, Hal Weidmann (CHRISTOPER WALKEN), won't let anyone see the film until it's unveiled before the press.
Nevertheless, and arranging to have his old job back, Lee sets out to work his magic. Setting up the press junket at a remote desert resort, Lee convinces Eddie to attend and promote the film, and calls on Gwen's personal assistant and sister Kiki (JULIA ROBERTS), to convince the starlet to do the same. As the reluctant and soon-to-be ex-husband and wife arrive on the scene, Lee does whatever he must to keep the stars and press happy, all while Kiki and Eddie soon begin to feel more than friendship toward each other.