The songs of ''My Best Friend's Wedding''

When Julianne (Julia Roberts) gives a present to her pal Michael (Dermot Mulroney) and his new bride (Cameron Diaz) at the end of My Best Friend’s Wedding, it’s appropriately a gift of song — for the summer’s hit date movie is at heart a classic movie musical. Unlike offbeat efforts such as Woody Allen’s Everyone Says I Love You, director P.J. Hogan achieves the impossible in these cynical times: a true marriage of musical conventions and romantic comedy.

Having characters burst into song is a gambit that yields Wedding a banquet of charm — captured on the soundtrack album, which just jumped 86 slots on the Billboard 200. In the film’s title sequence, bridesmaids lip-synch Ani DiFranco’s ironic cover of ”Wishin’ and Hopin’.” Later, Diaz croaks Burt Bacharach’s ”I Just Don’t Know What to Do With Myself” at a karaoke bar, and, most memorably, Rupert Everett (as Roberts’ gay confidant) leads a wedding party in a rousing rendition of ”I Say a Little Prayer.”

”Music gets all your senses going at once,” says Bonnie Greenberg, the film’s music supervisor. ”These days, movie music is about selling records, not the extra level of emotion it brings.”

Hogan, who found unimagined nuances in ABBA’s oeuvre for 1994’s Muriel’s Wedding, lets the music say what the characters can’t. Which isn’t always pretty.

Diaz’s karaoke scene is beautiful and anguished. ”Cameron had been practicing [her lip-synching],” recalls Greenberg, ”but P.J. decided it would be better to see if she could sing it live, then she’d be embarrassed, like her character.”

As for the ”I Say a Little Prayer” scene? Greenberg says Hogan took no chances. In a sound studio, where the music was recorded before filming began, ”he sat everyone around a table and actually directed the scene in his head as we were recording…. P.J. has an incredible eye and ear for these numbers. He’d do an incredible job with an actual musical.” Maybe an update of The Gay Divorcee?