“Sequels,” says Chili Palmer (John Travolta) with visible condescension.

And from the first word uttered, “Be Cool” establishes that it’s not so much a traditional movie as it is a loose collection of self-referential gags.

Similar to “Ocean’s Twelve,” this comedy unfolds like a two-hour in-joke that is rarely dull but only occasionally as funny as it thinks it is.

The caper-style plot is secondary to the characters, who are played by a somewhat inspired group of actors and musicians. They represent a weird hybrid of the real and artificial. Rapper Andre 3000 of Outkast portrays a trigger-happy thug, while singer Steven Tyler of Aerosmith plays himself.

This sequel to 1995’s “Get Shorty” (both based on Elmore Leonard novels) again centers on the subdued Chili. The former mob collector — dubbed a “shylock” — has grown disenchanted with his recent success in the movie industry. He wants a new challenge, and a young singer named Linda Moon (Christina Milian) provides him with the opportunity to tackle the music world. He soon learns that this profession is far more dangerous than what he encountered during his criminal days.

“At least they’re honest about being dishonest,” he says of the mob with nostalgia.

Before long, a contract dispute with a major record executive (Harvey Keitel) and a partnership with the widow (Uma Thurman) of an indie label owner has turned the heat on Chili. After angering everyone from a Suge Knight-type rap producer (Cedric the Entertainer) to a low-level white exec who thinks he’s black (Vince Vaughn) to the Russian Mafia, Chili must find a way to avoid being killed long enough to make his new client a superstar.

It appears the cast and crew are enjoying themselves in “Be Cool.” There’s a breezy, improvised feel to the proceedings that is infectious even though the story itself is overcomplicated.

It’s nice to see Travolta anchor a movie with a likable character for a change rather than brood (see “The Punisher”) or munch-the-scenery (see “Battlefield Earth”). He comes across as focused in this role, particularly during the many scenes where he tries to talk his way through a situation instead of resorting to violence.

But the real standout in “Be Cool” is Dwayne Johnson, aka The Rock.

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The performer has always shown a great eye (or eyebrow) for comedy. (His turn in “The Rundown” revealed skills beyond that of a muscle-bound action star.) The former wrestler plays Elliot, a gay Samoan bodyguard who is far more concerned with breaking into the music industry as a country singer or the film industry as an actor than he is protecting his loudmouthed boss (Vaughn). And he sure loves those Howdy Doody outfits.

This leads to a truly surreal scene, in which Elliot busts into Chili’s house to threaten him and ends up auditioning. Yet when asked to perform a dramatic monologue he selects a multipart conversation from the cheerleading movie “Bring It On.”

It’s this type of inspired lunacy that helps balance out the contrived lunacy that director F. Gary Gray (“The Italian Job”) inserts into the narrative.

This artificial aspect exposes itself in a dance sequence involving Travolta and Thurman set at a Black Eyed Peas concert. Obviously it’s an attempt to recapture the magic of the Jackrabbit Slim’s contest from “Pulp Fiction.” Thurman looks better than ever in her hip-hugging hipster outfits, and Travolta displays the footloose skills that originally made him an idol to millions.

But the whole thing seems so calculated that it only serves to grind the plot to a halt.

It’s one of several musical numbers that fall flat, including a syrupy piano ballad delivered at a youth center by the Alicia Keys wannabe Milian. Add to that a duet between her and Tyler at an Aerosmith concert, and the whole thing starts to feel more like an ad for the soundtrack.

Singer-actress stays ‘Cool’ in new movies (03-04-05)

Mixing real celebrities into the plot of a movie is a dicey proposition. It can result in an easy laugh or it can suck the viewer right out of the story. When partnered with obvious marketing it starts to become especially prickly.

Perhaps this is best typified by an early scene when Thurman’s character is spotted sunbathing by the pool and it’s divulged she has an Aerosmith tattoo across her lower back. At first the sight gag is amusing. As the film progresses it seems more like product placement. “This space for rent.”