Two types of comedies struggle for control in _America's_Sweethearts_: one, a catty satire of the Hollywood hype machine; the other, a frothy star vehicle for America's apparent real-life sweetheart, Julia Roberts. Coming out the loser in the ensuing mess is Joe Roth, who shows that spending the last ten or so years heading movie studios hasn't done any favors for whatever directorial ability he may have once had.

From the looks of it, _America's_Sweethearts_ started out as an edgier ensemble picture, and shades of that appear in the film's more effective portion, the first half. The sweethearts of the title are beloved off- and on-screen pair Gwen Harrison (Catherine Zeta-Jones) and Eddie Thomas (John Cusack), who fell in love on the set and then proceeded to make a string of popular co-starring vehicles after getting married. Alas, the fairy tale came to an ugly end after Gwen fell in love with another co-star (Hank Azaria) on the set of their latest movie, the sci-fi romance _Time_Over_Time_, which is now being readied for release. It's up to seasoned publicist Lee Phillips (Billy Crystal) to make sure the two put on their best faces--and not kill each other--during the multi-day, hotel-set publicity ritual known as the press junket.

The basic premise of _America's_Sweethearts_ paints the film as being almost too inside. After all, the story of a press junket being in danger is one that could only be understood, much less appreciated, by journalists and others with a keen knowledge of the workings of Tinseltown's PR process. That said, some effective zingers (by Crystal and Peter Tolan) directed at big studio glitz provide some amusement for less showbiz-savvy audiences, as do some inspired performances by Stanley Tucci, who plays a nervous studio chief; Christopher Walken, who plays the eccentric, reclusive director of _Time_Over_Time_; and Zeta-Jones, who obviously has a ball playing the stereotypical self-absorbed screen diva.

But somewhere along the line Julia Roberts decided to get involved in the picture--not as the ostensible female lead, Gwen, but in the more secondary role of Gwen's put-upon sister/personal assistant Kiki. Roth then beefed up the Kiki role in fair proportion to the "JULIA!" stature as any self-respecting studio head/businessman would. However, this turns out to be a ruinous miscalculation not only in terms of storytelling but in simple casting. Kiki is supposed to be frumpy and a bit of a loser, and regardless of whether or not you think Roberts is the "pretty woman" she's celebrated as being, her charisma and natural star wattage is undeniable and just about impossible to quash. Not even a fat suit, which she wears in some flashback scenes, is able to obscure the fact that it's "JULIA!". So when Kiki and Eddie start to develop feelings for each other (which isn't giving away a thing that isn't already revealed in the trailers or that could be easily predicted), what should have been a mere plot complication becomes the focus, and suddenly "America's Sweethearts" transforms into a "JULIA!" star vehicle about how she gets the guy--and an especially weak one at that, given the glacial non-chemistry between her and Cusack.

Not that _America's_Sweethearts_ is too successful in general comedic terms. Apparently having little faith in the sometimes-spicy ideas and dialogue as well as the talented actors delivering them, Roth throws in the broadest lowest-common-denominator slapstick gags whenever he can. A feisty, ferocious dog takes an unnatural liking to Lee's crotch. While jogging through a golf course, Lee's underling Danny (Seth Green) gets hit in the head with a ball. And the point is...? Certainly not laughs, for those goofy goings-on land with a thud.

Then again, the whole of _America's_Sweethearts_ doesn't seem to have a point, either, given its split personality. Roth would have been wiser to choose between making a movie publicity send-up or a "JULIA!" showcase, for in trying to achieve the best of both worlds, he ended up shortchanging the audiences for either.