"America's Sweethearts" has an intriguing premise and a great cast, but it isn't nearly as edgy or funny as it should be. Almost all the problems with the project can be traced back to co-script writer Billy Crystal, who shows the same lack of discipline with the screenplay that he typically displays while co-hosting "Comic Relief" charity shows with Robin Williams and Whoopi Goldberg (two other paragons of self-indulgence).

Crystal ignores a simple, but crucial, rule: For a screwball comedy to work, the characters must be placed into a rigid social setting, because only in that context will their unorthodox antics be humorous. "America's Sweethearts" takes place at a press junket, where decorum must be maintained in front of the reporters. It's a promising set-up, but the screenplay quickly blows off the rules, thus dissipating the tension of the situation. By the end of the film, all the lead performers participate in a huge fight with a room full of journalists looking on, but their outbursts are only mildly amusing because the structure has been destroyed.

John Cusack and Catherine Zeta-Jones play Eddie Thomas and Gwen Harrison, a beloved acting duo whose marriage hit the skids when Gwen began seeing Hector (Hank Azaria), a Spanish actor with an ego almost as pronounced as his lisp. Of the last nine films Eddie and Gwen made together, six crossed the $100 million mark, but the prospects for their final effort, a space opus titled "Time Over Time," are far from rosy. While Eddie has spent many months in a New Age rest clinic fretting over the breakup, Gwen's solo films have tanked. To make matter worse, the director of the movie (Christopher Walken), a "visionary" who purchased the Unabomber's cabin and had it moved to his backyard, is withholding the film from the studio, insisting that the first screening be held at the junket.

Desperate to win over the press, the studio elects to hire Lee (Billy Crystal), a recently fired publicist, to salvage the situation. Lee hopes to turn lemons into lemonade by convincing Eddie and Gwen to pretend to be on the road to reconciliation. He enlists the help of Kiki (Julia Roberts), Gwen's sister, personal assistant and whipping girl. What Lee doesn't know is that Kiki is in love with Eddie, a fact that could temper her effectiveness.

Press junkets are a haven for control freaks. Studios fly journalists in from around the world and put them up in a plush hotel, with food and drink always at hand. Generally, on the evening of their arrival, writers are bussed to see the featured film, then ferreted straight back to the hotel. The next day, writers go to the studio suites and assemble in groups of five or six for roundtable interviews. Every 30 minutes or so, a producer, director, writer or actor is brought into the room for a few minutes of questions, with a publicist hovering in the corner to keep an eye on things. The atmosphere is one of cordial oppression – writers are free to ask what they want, but understand that if the studio dislikes a question, they may not be invited to future junkets.

Representatives from TV stations face even more restrictions. They get roughly five minutes to interview each member of the cast and crew, with the studio filming the exchanges. The "reporters" are notorious for tossing softball questions as they suck up to the stars, but to play it safe, the studios stand ready to erase the tapes if anything unpleasant occurs.

Placing two spoiled actors in a setting where image is everything is inspired, but the screenplay undermines the conceit. The junket is moved from the handsome, but highly confining, Four Seasons Hotel to a plush resort near Las Vegas. For most of the film, the movie stars run around the sprawling grounds, completely safe from the eyes of the press. When they do deal with journalists, the "it is imperative that you be on your best behavior in front of the reporters" premise is de-clawed. Gwen and Eddie insult each other while the TV cameras roll, they scream at each other in a restaurant filled with the media and, at the screening of the movie, everyone connected with the film goes nuts, all without any repercussions.

Lee certainly isn't bothered by any of the infantile outbursts; in fact, he makes arrangements for footage of even more inappropriate behavior to be delivered to the tabloids. Is the studio angry about his handling of the combative actors? Hell no – they feel Lee is a genius for garnering so much publicity for the movie.

All of which underscores how Billy Crystal and co-writer Peter Tolan screwed up their own premise: The comedy in "America's Sweethearts" is based on barely-in-control people trying to contain themselves in the presence of reporters, except that it doesn't matter because any publicity is good publicity. And thus the very set-up for the film implodes, leaving smoke and dust in place of laughter.

So what about the cast? Julia Roberts, at her best playing the underdog, is utterly charming here, although I could have lived without flashbacks that exist solely as an excuse to show her in a fat suit (and not a very convincing one, by the way). Catherine Zeta-Jones makes a believable brat and John Cusack fleshes out his obsessed character enough to make him vaguely sympathetic. By casting himself as the publicist, Billy Crystal allows himself to do roughly the same thing he does on "Comic Relief"- stay on the sidelines of the action while tossing off cornball jokes and snarky remarks.

In supporting roles, Hank Azaria wears out his welcome fast with broad gestures and a Spanish accent that Speedy Gonzales would have deemed "too broad." Seth Green is amusing as a toadie, Stanley Tucci is very good as a ruthless studio head and Christopher Walken plays the eccentric director with suitable flair, though he has little to work with.

Come to think of it, "little to work with" is the operative phrase for this movie. As a Hollywood satire, "America's Sweethearts" is toothless. As a romance, it is at best a minor pleasure. Such a good cast, such a waste of their efforts. Had it not been taken long ago, a better title for the film would have been "Much Ado about Nothing."