HuffPost Review: Get Him to the Greek -- Brand & Hill Rule; P. Diddy Surprises.

If you were fan of Russell Brand's rock star character Aldous Snow in 2008's Forgetting Sarah Marshall, then brace yourself for a hysterical spin-off with Get Him to the Greek.

Paired with Jonah Hill (who does not reprise his waiter role in Marshall) the duo make an unlikely pair in this hilarious buddy road trip comedy written and directed by Nicholas Stoller, who also helmed Marshall.

Hill plays Aaron Green, a young record executive who has been leading a peaceful life with his girlfriend Daphne (Mad Men's Elizabeth Moss). Just as the couple hits a rough patch, Aaron's record mogul boss, Sergio Roma (Sean 'P. Diddy' Combs), assigns him the mission of a life-time: he has three days to drag a boozing, drug-taking, sex crazed rock n roll star Aldous Snow (Brand) from London to Los Angeles where he is scheduled to have his comeback concert at the Greek Theater.

Along the way, there are pit stops in New York and Las Vegas, not to mention encounters with Aldous' dysfunctional father (Colm Meaney) and detours to win back the love of Aldous' life, model/pop star Jackie Q (Damages' Rose Byrne) with whom the rocker has a son.

The film is a laugh out loud romp much like The Hangover was last summer. It's not so much where these two go, but the ride they embark on and how it all seems to constantly veer off track with sex, drugs and rock n roll. Just when they seem to get themselves together, one or more of these variables comes along to make go haywire again. One can say it's more like an R-rated version of Planes, Trains and Automobiles. It's crude, hysterical, yet possesses an underlying sweetness that prevents it from falling in to something more juvenile and immature.

The various music videos and songs are brilliantly thought out, with some of the lyrics written by Marshall actor/screenwriter Jason Segal, who co-produces Greek.

The real-life cameos by the likes of Pink, Christina Aguilera, Pharrell and Metallica's Lars Ulrich add to the realism of Aldous' rock star status. The insertions of shows like The Today Show, Access Hollywood, MTV News, and others make Aldous' attempted comeback feel immediate and current, especially when hosts like Meredith Vieira literally become part of the plot.

(Side note: Katy Perry also shot a cameo for the film. Shortly after, she and Brand began to date and are now engaged. That piece of realism, however, was not brought in to the film as Perry's scenes were cut.)

Brand's work as an actor largely unknown to American audiences, who know him primarily from his work in Marshall and hosting the MTV Movie Awards last year. Therefore, it is impossible to know where Brand ends and Aldous Snow begins. In public and on screen, both appear to be the modern versions of Johnny Depp's Captain Jack Sparrow in Pirates of the Caribbean. No matter what the answer is, the end result is a character that is so charismatic and out there, one can't help but be drawn to him.

Greek is also a showpiece for Jonah Hill, who is playing his most grown up role to date. He's no longer the sarcastic guy we knew from Superbad, but a well rounded character with a more serious and softer side. As the one who bears the brunt of Aldous' excesses, Hill comes across as a young John Candy - funny, vulnerable and fallible. It will be interesting to see the choices this young actor continues to make in his career.

The two women in Greek, Moss and Byrne, get to shed their TV images and really shine in these comedic roles.

P. Diddy must also be commended. The rap mogul sheds his posturing rap persona and it's an absolute delight to watch. Though there are moments where he seems stiff and self-conscious there are genius scenes where he completely lets go. In the Vegas hotel suite and its ensuing chase sequence, for instance, he's the scene-stealer ("You can't outrun me - I'm black!"). To see P. Diddy willing to make fun of his music mogul persona is an unexpected surprise as he certainly has not made a career for himself as a person with a sense of humor.

If Diddy can keep this up, perhaps one day we'll get to see a Sergio Roma spin-off feature.