Sequels usually maintain a certain consistency from their source material. Even if it isn't a direct continuation of the original story, the characters and their places within the fictional universe are more or less set in stone.

With "Get Him to the Greek," director Nicholas Stoller creates an interesting deviation from the normal sequel template by recycling a character from his earlier movie, "Forgetting Sarah Marshall," and recycling two actors from the same, but having one play a different character altogether. While it's a decision that could have been confusing, Stoller manages to keep what he wants from "Marshall" without being weighed down by the attendant baggage that usually comes with creating a follow-up.

The returning character is Aldous Snow (Russell Brand, "Bedtime Stories"), an aging, late-'90s Brit-rock star whose career has diminished after the release of an indulgent "political statement" album called "African Child." Snow has retreated from the world and sobriety, holing up in his London apartment with his mum, assorted lackeys and substances.

Jonah Hill ("How to Train Your Dragon"), who played a waiter in "Marshall," is now cast as Aaron Green, a low-level Los Angeles record company employee. When his boss, Sergio (rapper Sean "P. Diddy" Combs) demands moneymaking ideas from the staff, Aaron suggests staging a 10th-anniversary concert of Snow's famous performance at L.A.'s Greek Theater. Sergio sends Aaron off to jolly old London town to pick up the notoriously spaced-out Snow and bring him back to the States for a TV appearance in New York, then to the West Coast for the concert.

With this fertile premise set up and in motion, it's up to Brand and Hill to play off each other as the wild man and straight man, respectively.

As with any road movie, "Get Him to the Greek"'s success rests on the strength of the gags and the overall energy. The chemistry between Brand and Hill is perfect, which is probably why Stoller broke the sequel rules and brought Hill back in a different role. But the show-stealer is Combs, whose straight-faced madness actually rivals and counterpoints Brand's wide-eyed zaniness. It isn't too much to say that without him, especially in the Las Vegas sequence, "Greek" would have lost about 20 percent of its charm.

That energy begins to flag toward the end as Aldous and Aaron both have to learn lessons about who they are, who they want to be and blah blah blah. While the absurdist closing song somewhat manages to tie the insanity of the film's hedonistic framework to its moral center, there's a certain sentimentality that doesn't quite square.

One gets the impression Stoller shot more story than he had room for, and the end's crowded feeling may indicate difficulty in deciding what to cut and keep. It doesn't ruin the movie by any means, but as the only weakness in an otherwise near-perfect comedy, the mushy psychological stuff is a bit disappointing. "Mike Robertson