How to put this politely? Though frequently riotous, Get Him to the Greek, the Forgetting Sarah Marshall spin-off with Russell Brand and Jonah Hill reprising their characters as shaggy British rocker Aldous Snow and his fawning fan, is Hamburger Helper with more helper than hamburger. This time, the supporting players are the stars.

Yet even while these secondary figures don't fully rise to leading-man dimensions, the film succeeds as a music-industry satire, a very naughty version of Almost Famous. This time, the fanboy does not write the legend of the rocker but restores him to former glory. Call their misadventures - which involve more sex, drugs, and rock-and-roll than Keith Richards indulged in during his debauched days - Almost Infamous.

Resembling a Goth Willy Wonka, Aldous - who once topped the charts with his album Infant Sorrow - releases a new album, African Child. Promptly it is denounced as the worst thing to hit that continent since apartheid. After the bad reviews and the breakup with his Spice Girl-type wife, Jackie Q (Rose Byrne), Aldous hits the skids and the bottle.

Back in Los Angeles, music-industry executive Sergio Roma (P. Diddy, unexpectedly funny) is about to cut Aldous loose. Then Aaron (Hill), a puppyish junior exec at the label, suggests mounting a comeback concert on the 10th anniversary of Aldous' celebrated live show.

Now all they have to do is get Aldous, who drinks his weight in beer every morning and consumes heroin like cornflakes, from London to Los Angeles' Greek Theatre for the gig. Hence the film's title.

Director Nicholas Stoller (who likewise helmed Sarah Marshall and is a charter member of the Judd Apatow fraternity) ticks off the differences of this mismatched duo for Laurel-and-Hardy comic effect.

Aldous is lean as a string bean; Aaron round as a doughnut. Aldous is a loose cannon; Aaron is firmly anchored. Aldous has no emotional ties; Aaron has a live-in girlfriend (Elisabeth Moss, a medical resident).

Predictably, this study in excess and moderation crashes like particles in a comic Supercollider over their 72-hour power struggle, set in the self-contained universe of NBC/Universal. (Many of the film's pivotal scenes cross-promote the corporate brands. After a wild plane ride from London, Aaron gets Aldous to NBC's The Today Show, where a baffled Meredith Vieira surveys the damaged duo. Monitoring his star and assistant by cell, Sergio watches NBC's The Biggest Loser. The Greek Theatre itself is a venue owned and operated by Universal Studios.)

Except for a sequence in Las Vegas involving a wall upholstered with fur, the scenes between Aldous and Aaron are never as funny as those between the men and their women. Delicate as she is prickly, Byrne's Jackie works her English-rose beauty to entice and punish Aldous. And as Daphne, Moss (best known from Mad Men), so self-possessed with Aaron, is comically flustered in the face of Aldous' debauched logic, delivered in his irresistible singsong.

Great? No. Great fun? Oh, yes. Like Sergio and Aldous, this movie messes with your mind, then tickles it.EndText