'Step Brothers' (R)(out of four)

Will Ferrell's track record for comedy has been impressive, but hardly perfect. He's scored with hits like "Elf," "Talladega Nights," and "Blades of Glory," but failed to deliver the goods with more dismal films such as "Kicking and Screaming" and most recently, "Semi-Pro."

But with his latest effort, "Step Brothers," the former "Saturday Night Live" funnyman is once again is firing on all cylinders -- aided in no small part by a wonderful team of co-stars.

Ferrell plays Brennan Huff, a 39-year old slacker who is still happily living at home after getting laid off from his job at the local PetSmart. He's looked after by his kind but perhaps too-understanding mother, played to perfection by Mary Steenburgen.

His lazy existence gets turned upside down, however, when mom falls in love with a doctor (veteran character actor Richard Jenkins) and the two decide to marry and move into hubby's home. The good doctor has some baggage as well: namely, 40-old son Dale (the always fantastic John C. Reilly -- Ferrell's co-star from "Talladega Nights," whose lack of personal initiative equals that of his new stepbrother.

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These two reluctant relations warily eye each other and soon go to war after being forced to share a room. Why they battle over the most miniscule things is a plot point probably best understood by anyone who ever roomed with another sibling. Things escalate rapidly: Dale forbids his stepbrother from touching his beloved drum set, which of course Brennen does with relish, making sure a very personal part of his body makes contact with the instrument. They also try to bury one another alive in their back yard.

But before these two can kill each other, they find themselves slowly bonding over a mutual dislike of something bigger than both of them: Brennan's "golden boy" brother Derek (excellently played by the smarmy Adam Scott from HBO's "Tell Me You Love Me"). Derek is successful and has an all-too-perfect family that he leads in bizarre sing-a-longs in their car.

He manages to quickly win over his new stepdad, who gushes with admiration, much to the disgust of the other two "boys." Naturally, he mercilessly ridicules Brennan and Dale whenever an "adult" isn't looking (think Eddie Haskell from "Leave it to Beaver"). Unbeknownst to "image is everything" Derek, the boys aren't the only ones who see through his act. He's equally despised by his wife (played with neurotic relish by Kathryn Hahn from "Crossing Jordan), a pent-up woman who becomes obsessed with the sexually naïve Dale after she witnesses him stand up to her husband, leading to some of the movie's more outrageous scenes.

The story for "Step Brothers" was developed by Ferrell, Reilly and director Adam McKay (who also directed Ferrell in "Anchorman") after they finished shooting "Talladega Nights." They've nailed the often-rocky relationship between brothers, from misadventures like building ill-fated bunk beds and coming to the realization they have to act like adultscomma to coming together as brothers to step up and save the day. (For more entertainment, make sure to stick around for the end credits.)

"Step Brothers" does have its share of gross-out jokes (hey, it was produced by Judd Apatow of "40-Year-Old Virgin" fame) but in the end, it's a movie that delivers a surprising amount of heart.