George Simmons (Adam Sandler) has it all. Money, fame, a big house, legions of beautiful women who'll sleep with him because he's famous. Basically, he's living the Playboy lifestyle. What George doesn't have is friends, acquaintances, family - his fame has left him isolated and lonely, and when he gets the worst news of his life, he discovers that no one really gives a damn about him. They love him for his lowbrow comedies, but no one knows George Simmons.

After a disastrous appearance at a comedy club, George finds himself the object of ridicule by a guy named Ira Wright (Seth Rogen), a funny writer but horrible performer. Seeing something in Ira's writing, and seeing a need in himself to give something back and make one legitimate connection before his health takes a turn for the worst, George reaches out to Ira. Not as a friend, but as a writer and personal assistant. George has his affairs to get in order, but he discovers along the way that he needs more than just a lackey; he needs friends. With a death sentence over his head, George needs to start making right all the ways he's gone wrong, starting with Ira and transitioning to the girl that got away, Laura (Leslie Mann).

In some ways, Funny People is Judd Apatow's best film. It's legitimately moving at points, uproariously funny at other moments, and there is actual emotional development in the character of George Simmons. That said, it also has all the flaws of a Judd Apatow film, despite lots of improvement over his standard movie.

You'll get sucked in by Adam Sandler's brilliant performance. This is by far his best work, even better than his out-of-nowhere performance in Paul Thomas Anderson's Punch Drunk Love. For the first hour and a half, he is staggeringly good as George Simmons. His anguish at the way he's lived his life and his abject loneliness had to have appealed to Sandler because, well, he is basically George. Like George, he's made his fortune on awful comedies and, like George, he can't go out in public anymore without being mobbed by fans. Like George, he has to live something of an isolated life because he's Adam Sandler. (Eminem's cameo appearance really cements this in a hilarious way.) Sandler really digs into himself for this tragic character, and he produces a starmaking performance that should hopefully make up for the snubbing he received for his earlier attempts at straight acting.

The others in the film, specifically Seth Rogen, Jonah Hill, and Jason Schwartzman as a trio of budding actor/comedians, are also very good. There's definite chemistry between them, and legitimate friendship that comes through on the screen and adds to their exchanges with one another.

I've been getting bored with Seth Rogen's act lately, and his new physical body (slimmed down quite a bit) comes with a new, toned-down style in which he, gasp, seems to have grown up a little! Eric Bana makes a good comic villain, and Leslie Mann does well as the one that got away, injecting some of the only comedy in the film's misguided move to Marin County. The biggest sign of Apatow's growth is in supporting characters like Dr. Lars (Torsten Voges) and Randy (Aziz Ansari), who are both scene-stealers and (in the case of Dr. Lars) layered. There's no one-dimensional character getting extended screen time.

The fact that Apatow went out to get brilliant cinematographer Janusz Kaminski suggests that he's really trying to work on his weaknesses and direct better films. In some ways, he's succeeded, but in some ways his one-man show and insistence on casting nothing but his friends and family hampered him. Sandler, Rogen, Hill, Schwartzman, and company work, but there's entirely too much of his family involved, specifically his children. Most of the cuddly kid scenes could safely end up on the cutting room floor. Apatow gets his vision to the screen, and more power to him for it, but a little outside help in the editing room would've improved the film immensely. It's not that the San Francisco stuff is bad (it's still interesting), but it just meanders in comparison to the tight action in LA. The film, like George, loses its way.

Funny People is a film about growth. As George Simmons grows as a person, Adam Sandler grows as as a performer and Judd Apatow grows as a director. It's not perfect, but life isn't perfect. Apatow's next step will be to put together a film that's under two hours long. It's reassuring to know that everyone, no matter how rich or famous or accomplished, has room to grow.

Funny People isn't Judd Apatow's most polished movie, but it is his most ambitious project to date. It's a bold venture from a guy not known for his maturity. He steps out onto the ledge as a writer and filmmaker, and he's risking a great deal. Kudos to him; he could've rehashed his usual fare and made a hundred million dollars, but instead he's chosen to dig deeper and-for the most part-it works.

Funny People opens in the UK on the 28th August. It's playing in the US right now.

US correspondent Ron Hogan has trouble reviewing films that speak to him without boring you with his personal life. Find more by Ron at his blog, Subtle Bluntness and daily at Shaktronics and PopFi.