Eight years in the making as a collaboration between the multiplatinum rappers and their college buddy, Bryan Barber (who directed several of the group's videos as well as clips for Destiny's Child, Kelly Clarkson and Christina Aguilera), "Idlewild" follows two musicians in small-town in Georgia in the 1930s: singer, club owner, mack daddy and errant family man Rooster (Antwan "Big Boi" Patton) and his childhood friend, Percival (Patton's OutKast partner, Andre "Andre 3000" Benjamin), a mortician by day and shy piano player by night.

In interviews promoting the film -- which was accompanied by a soundtrack with the same name released on Tuesday and marketed as the eagerly-awaited follow-up to the duo's 2003 smash "Speakerboxxx"/"The Love Below" -- Patton and Benjamin said they wanted to make a modern musical that was more "Purple Rain" than "Singin' in the Rain." But "Idlewild" isn't a romanticized autobiography and showcase for live performances, like Prince's 1984 movie, any more than it's a traditional old-school musical like the 1952 Gene Kelly classic -- though the characters do spontaneously break into song at times, as when Percival inexplicably serenades a body on the mortuary slab.

OutKast did get one thing right with that rainy comparison, though: The movie is often a soggy mess.

To be sure, there are good things about "Idlewild." Unfailingly charismatic, Patton and Benjamin both have considerable potential as stars, and they're ably supported by a top-notch cast that includes Terrence Howard ("Crash," "Hustle & Flow"), Ving Rhames ("Pulp Fiction," "Mission: Impossible"), Faizon Love ("Elf," "Friday") and "Roots" veterans Ben Vereen (as Percival's dad) and Cicely Tyson (in an all-too-brief cameo as a Dust Bowl refugee). Proudly freaky R&B singer Macy Gray also does her best as a slutty vamp, and newcomer Paula Patton (no relation to Antwan) makes a memorable debut as Percival's love interest, Angel.

Shot in a style that's part MTV and part wannabe-"Chinatown," the movie lovingly if sometimes fancifully re-creates the era -- all of the characters seem to be living fairly high on the hog, despite the inconvenience of the Great Depression. Choreographed by three-time Tony winner Hinton Battle ("Dreamgirls"), the handful of dance numbers are an exciting mix of '30s jive and modern break dancing. And while the basic story is a bit hoary -- I'm spoiling nothing in revealing that Rooster eventually abandons the thug life to tend to his family, while Percival loses Angel but makes it to the big time in Chicago (hey ya!) -- is nonetheless effective, up to a point.

That point would have been about 85 minutes in, though the movie runs for nearly two hours. And if Benjamin solemnly intoning the famous quote from Shakespeare's "As You Like It" ("All the world's a stage, and all the men and women merely players...") was cheesy at the start of the film, it became annoying in the middle and downright stupid when it was repeated a third time near the end.

In addition to this unnecessary fat in serious need of trimming, "Idlewild" suffers from a lack of focus, trying to be something for everyone: It's a love story; a sub-"Scarface" gangster movie (complete with sudden and jarring eruptions of violence) and a buddy film -- though the relationship between Patton and Benjamin is seriously underplayed, adding more fuel to the speculation that OutKast is destined to split. Most of all, though, it's a musical -- which, again, is its biggest shortcoming.

As songwriters and producers, Benjamin and Patton seem to have little real affinity for this era. In his big production numbers, Benjamin doesn't seem to know whether he wants to be Cab Calloway, Duke Ellington or Louis Armstrong, so he tries to channel all three simultaneously, upping the flamboyant silliness and minimizing the fact that he can't really sing. Meanwhile, Patton appears to enjoy his bad-boy lover-man role and the natty clothes, but he seems embarrassed by the hackneyed attempts to summon period sounds, so he just tries to rap through his numbers as quickly as possible, as if rapid-fire flow will prevail over pervasive cheese.

In the end, the saddest thing about "Idlewild" is that all of the pieces were present for a very good film. But Patton and Benjamin, who have accepted few stylistic restraints over the course of six wildly inventive albums, for some reason felt compelled to limit the music to a sound and style they just didn't feel. By its very nature, a musical can never be super-realistic, and they didn't seem troubled by other whimsical touches like a talking rooster.

Who ever said that OutKast couldn't have powered a film set in a '30s speakeasy with non-'30s sounds? Songs as strong as the best this group has given us in the new millennium would have gone a long way to making a just-OK movie about the distant past something pretty special.