As a freshly heartbroken boyfriend, Jason Segel has wounded eyes, a naturally depressed countenance, and, in a most vulnerable of moments, an exposed penis. Fresh from a shower, he alights from the bathroom to find his long-term girlfriend, a television cop show star, breaking up with him.  He is naked, not even a modest towelette to cover his intimates.  The scene displays genuine vulnerability and is wincingly funny. Generally a bit player in the SuperFreaks ensemble, he shows in “Forgetting Sarah Marshall” that he is a strong presence when he‘s given a bigger part.  As Peter Bretter, the incidental music composer for his girlfriend’s show, Segel is pitch perfect as he excels in both the ribald situations and the delicate moments. 

Segel is the fulcrum of “Forgetting Sarah Marshall,” a film which follows Peter just weeks later to Hawaii, where by purposeful accident he stays at the same resort as Sarah and her new beau, Aldous Snow, a Rock God archetype, all shirts buttoned at the navel, if at all, played by English comic phenomenon, Russell Brand.  Long, lanky hair to the middle of his back, he exudes all the tubular swagger of The Cult’s Ian Ashbury with a sprig of Robbie Williams’ impishness.  And Brand is the film’s second revelation.

In England, he is a comic superstar. Ostensibly a standup, in reality the ebullient sex symbol is a gothic raconteur renowned for hysterical musings on chat shows and quiz programs. His reputation as a lothario is so celebrated that in recent years the sensationalistic tabloid The Sun dubbed him “Shagger of the Year.“  Brand’s style is narcissistic but whimsical and self abasing. The Radio 2 show he and good friend Matt Morgan host is two frantic hours of stream-of consciousness; the podcast is the BBC’s most downloaded. His autobiography released earlier this year in Britain was an instant bestseller and presented in his typically forthcoming manner. Brand’s the type of public personality who doesn’t draw a line between the personal and the professional, whose foibles and fables cohabitate.   

Segel, who wrote the script, clearly admires Brand’s comic style and allows him to infuse his performance with ramblings familiar to his radio audience. But Brand does not overwhelm the tone or derail the story. He’s no insurgent. And the lack of rivalry in this working relationship is mimicked by the absence of animosity shared between Peter and Aldous. It would have been the soft way to paint Brand’s character as an easy-to-loathe pomposity, a British over-the-top oaf. Yet the shirtless Aldous and vulnerable Peter actually quite like each other. So the anticipated “teat-a-teat” rivalry never materializes. And this development makes the eponymous Sarah Marshall, played ably enough by Kristen Bell, a peripheral character.

The Apa-in-tows — Paul Rudd, Jonah Hill and Bill Hader — all make an appearance and are pleasing interlopers without being memorable. And Mila Kunis as Peter’s new love interest  begins her hopefully successful emergence from the shadow of her eight years as Jackie on “That 70s Show.”

First-time director Nicholas Stoller shows restraint and stays out of the way. Some of the funniest moments are very quick visual gags which luckily make their point with brevity unlike too many SNL/”Superbad” overstayed-their-welcome skits. He also incorporates not one but two fantastic TV cop show send-ups which are so silly that irony deficient executives at the major networks will be dismayed they can’t debut them this fall. Reportedly, Stoller will helm Brand and Hill in “Get Him to the Greek,” a film built on the premise that a raucous wayward rock star — one suspects played by Brand not Hill —  must be chaperoned during a Los Angeles tour stop. It’s fingers crossed that it serves as a worthy successor.