After several flops in a row, Julia Roberts is looking for a hit.

And she may have found it with "My Best Friend's Wedding," which puts her back in "Pretty Woman" territory . . . in the sense that this frothy farce relies heavily on Roberts' comic charm to gloss over an unlikely plot.

But the movie itself is a disappointment, as director P.J. Hogan ("Muriel's Wedding") and screenwriter Ronald Bass ("Rain Man," "Waiting to Exhale") attempt a screwball domestic comedy in the vein of "Holiday" or "The Philadelphia Story."

You know the story — someone in love tries to break up a romance, or in this case, a wedding. The most recent '90s variation is "Addicted to Love," although that film is much darker than this one.

Roberts plays a New York food critic who is unable to commit to romance (she thinks love is just mush). And Dermot Mulroney ("Young Guns") is a traveling sportswriter with whom she was once involved. When they parted nine years ago, they vowed to remain "best friends" and have intermittently kept in touch over the years.

But when Mulroney announces he's getting married in Chicago, Roberts decides she actually loves him and flies out to disrupt the proceedings. There she meets the bride-to-be, wide-eyed and innocent Cameron Diaz ("The Mask"), a wealthy college student (and the only actress with a mouth wider than Roberts). Naturally, Diaz asks Roberts to be her maid of honor.

That doesn't stop Roberts from trying to throw a wrench into things, however. Her devious tricks start off small, as she tries to embarrass Diaz — who can't sing a note — in a karaoke bar. (Think Candice Bergen in "Starting Over.") But eventually, things get nastier, culminating in forged e-mail, which may cause audience sympathy to drop to a seriously low ebb.

Roberts' charm helps things out most of the way, but she has trouble staying above some of it. With something like this, you can either go full-bore into dark satire, or you can lighten it up as slick slapstick. Instead, the film never settles on a tone, and ultimately goes for thick sentiment in the film's second half.

Fortunately, there are some funny scenes (a hysterical sing-along of "I Say a Little Prayer") and some funny characters (Rupert Everett, as Roberts' gay editor, who steals every scene he's in).

Pumping up the comedy would have helped. As it is, it's an OK ride that probably won't doesn't warrant a return trip.

"My Best Friend's Wedding" is rated PG-13 for two extremely vulgar gags, profanity and comic violence. (The film was originally rated R, but got the PG-13 on appeal).