Three out of Five stars
Running time: 95 mins

Enjoyable comedy that wrings maximum laughs from its one-joke premise, thanks to terrific comic performances from Ferrell and Reilly.

What's it all about?
Step Brothers reunites co-stars Will Ferrell and John C. Reilly with Talladega Nights director Adam McKay. Ferrell and Reilly play 39-year-old slacker Brennan and 40-year-old slacker Dale, who suddenly become stepbrothers when their single parents (Mary Steenburgen and Richard Jenkins) meet, fall in love and decide to get married.

Dale and Brennan instantly hate each other, especially when it turns out that they have to share a room. However, they soon bond over a mutual dislike of Brennan's smug, over-achieving younger brother Derek (Adam Scott).

The Good
If you're a fan of Talladega Nights and you're already chuckling at the thought of Ferrell and Reilly playing squabbling step-siblings then you're pretty much guaranteed a good time with Step Brothers. As Talladega Nights proved, Ferrell and Reilly have terrific comic chemistry and Step Brothers basically delivers more of the same, while there's equally strong support from Steenburgen, Jenkins, Scott and Kathryn Hahn as Derek's wife, who keeps putting the moves on Dale.

There are some genuinely hilarious scenes, including: Dale and Brennan getting picked on by neighbourhood kids; Dale and Brennan's constant fights; Dale's tearful reaction to the news that his parents might be getting divorced ("Is it because of us?"); Dale and Brennan failing a job interview (with a cameoing Seth Rogen); and Scott forcing his family to harmonise to Guns N' Roses on the drive to Brennan's house.

The Bad
Although the filmmakers wring every last drop of humour from the premise, Step Brothers is still essentially a one-joke movie (it's painfully reminiscent of Twins in that respect) and your enjoyment of it will largely depend on how funny you find the basic set-up. In addition, the plot is extremely thin and the finale doesn't really work.

Worth seeing?
In short, there are plenty of good laughs here, but Step Brothers can't quite find enough of a plot to hang on its one-joke premise.