Julia Roberts sure has strange taste. Just as Academy members have their pencils ready to mark her down for an Oscar for Erin Brokovich, she pops up with Brad Pitt in The Mexican, which is the strangest big star collaboration of the year.

Roberts needn't worry; at a high point in her career, her star-power is invincible, and so is her paycheck. Pitt, on the other hand, is having a bit of a dry spell, unlikely to be helped by his star turn here. While The Mexican is at times fun, entertaining and sad, director Gore Verbinski doesn't do a very masterful job of blending its ingredients.

Pitt stars as Jerry, a likeable dope who gets himself mixed up in a crime ring. After failing on a recent job, his boss (Bob Balaban) sends him south of the border to retrieve an infamous (and seemingly cursed) pistol known as "the Mexican." He has no choice but to agree, breaking previous plans with his girlfriend Samantha (Roberts) to go to Las Vegas.

Samantha takes off for Vegas without him, but she encounters problems of her own: she's kidnapped by Leroy (a terrific James Gandolfini) to ensure that Jerry follows through with his promise to bring the gun back.

Jerry, meanwhile, scampers around in the desert pursuing the prize, attacking various thugs and adopting a dog in the process. Unfortunately, he's not the only one after the pistol, and his delay in bringing it back creates discomfort for everyone involved, particularly Samantha and the big bosses (headed by Gene Hackman).

More than one character in the film asks, "How do you know when enough is enough?" Apparently, Verbinski and screenwriter J. H. Wyman don't know how to answer that question. My answer would be, "when watching Brad Pitt and Julia Roberts in the desert gets dull." The film is overlong and filled with various subplots about the gun that seem unimportant in comparison to the interesting relationship between Pitt, Roberts and Gandolfini.

Obviously, the biggest draw of this film is its pairing of Pitt and Roberts. Fans may be disappointed to realize that they're separated for the first two thirds of the film. Roberts instead has most of her scenes with Gandolfini, which are the most enjoyable of the movie. Her chemistry with him is stronger than with Pitt.

In her scenes with Pitt, Roberts appears to be on speed. She screams and throws things at him like she's his crazed ex-wife. But when she's with Gandolfini, she calms down, opens up and gives us that signature smile, which makes Samantha a likeable character.

Gandolfini admirably handles the task of expanding his Sopranos hitman persona by digging deep into Leroy's hidden emotions. He asks Roberts, "Are you tawkin' to me?" with the same likeable zip of Robert De Niro, yet reveals a surprisingly fragile person through his eyes.

And then, of course, there's Brad Pitt. At one point, Samantha compares Jerry to Forrest Gump, and her comment isn't entirely inappropriate. The makers of the film seem to understand that part of Pitt's odd appeal is his spaciness. When we get a glimpse of Jerry's passport photo, it is no shock to see that his mouth hangs open and his eyes are wide like a space cadet. His relaxed and oddball air, contrasted with the native Mexicans, does provide for some entertaining moments.

Yet that doesn't hide the fact that the movie is one giant inconsistency. Verbinski can't seem to decide whether The Mexican is a romantic comedy, drama, thriller, western or just about anything else. The movie is strung together with pieces that don't quite fit, such as the gun flashback scenes. They're interesting in themselves, but contribute to the movie's puzzling tone.

Although there are some good elements and redeeming performances, The Mexican is a big bowl of movie mush. Open wide.