Finally this summer, a movie that lives up to its hype.

“Get Him to the Greek” is a complete blast, a much-needed breath of fresh air – well, as much fresh air as you can get in crowded clubs, packed rock shows and trashed hotel suites. But you get the idea. Its energy is what’s so refreshing, its lack of pretension or self-seriousness, especially during a season of bloated, boring blockbusters.

Like the 2008 hit “Forgetting Sarah Marshall” which inspired it, and like the other stand-out Judd Apatow productions such as “The 40-Year-Old Virgin,” ”Knocked Up” and “Superbad,” ”Get Him to the Greek” is primarily here to offer up a good time, with rapid-fire jokes, great pacing and (of course) a litany of clever pop-culture references. But there’s always that layer of humanity and sweetness that sneaks in, providing some heart along with the raunchiness.

Russell Brand’s performance was one of the funniest, most memorable parts of “Forgetting Sarah Marshall,” and here he reprises the role of preening British rock star Aldous Snow. Brand stole that movie in just a few scenes, and a little of this character would seem to go a long way. Aldous is self-centered, arrogant and condescending. People are disposable to him, and he’s incapable of being loyal.

He’s also flat-out brilliant and highly verbal, with a quick wit and an arsenal of hilariously off-kilter quips and observations. So he’s sort of a fascinating mix of contradictions, and a guy you wouldn’t mind hanging out with and partying all night – just to see what happens.

But “Forgetting Sarah Marshall” director Nicholas Stoller, who directed and wrote the script this time based on Jason Segel’s characters, also shows Aldous’ vulnerability, his caring side and even a darkness in expanding the role. “Get Him to the Greek” might actually go to some places that are too uncomfortably dark, its only weakness. But Brand seems comfortable and confident throughout, and the stand-up comic shows he’s capable of more than just earning laughs.

When we first see him in “Get Him to the Greek,” Aldous has released his latest album, “African Child,” to universal critical derision. (The video for the title song opens the film, and it’s a scream.) At the same time, he’s also just been dumped by his longtime girlfriend and the mother of his son, model/pop star Jackie Q (Rose Byrne in a beautifully deadpan turn as a clueless, vapid musician). So after years of sobriety, he’s now numbing the pain with booze, drugs and as many women as he can find: basically living the cliched rock-star life.

But up-and-coming record executive Aaron Green (Jonah Hill) has an idea: stage a 10-year-anniversary concert of Aldous’ legendary show at the Greek Theatre in Los Angeles. It’ll provide a jolt not just to Aldous’ career but his own, and hopefully impress his mercurial, demanding boss, Sergio Roma (Sean Combs, a scene-stealer himself).

Hill is the straight man again, as he was opposite Brand in “Forgetting Sarah Marshall,” but he’s not playing the same character. Both guys share a fawning admiration for Aldous’ work. In “Get Him to the Greek,” at least, this dynamic will change.

Aaron’s assignment is to fly to London and bring Aldous back to Los Angeles for the big comeback show. Naturally, this does not go as planned. There are wild stops in New York and Las Vegas, missed flights and anonymous romps, swigs of absinthe and smuggled drugs. Cameos from celebrities like Pink, MTV’s Kurt Loder and “Today” show host Meredith Vieira add a dash of realism to the adventures.

Part of the charm of “Get Him to the Greek” is that there’s a firm deadline – Aldous has to get there – but he’s taking his time, doing whatever he wants whenever he wants to do it, and Stoller revels in these detours. They also allow Aaron and Aldous to bond, and what’s intriguing about their relationship is that the power keeps shifting back and forth between them. Aaron isn’t constantly adoring, Aldous isn’t constantly abusive.

They actually, unexpectedly come close to being friends. And “Get Him to the Greek” comes close to being great.