Knocked Up is a smartly written tale about the mistakes that sometimes happen in the heat of lust.

The sort of mistakes that can radically alter lives or, as in the case of Judd Apatow's film, mistakes which unexpectedly bring new life into the world.

In his debut feature, The 40-Year-Old Virgin, writer-director Apatow mined a rich vein of comic gold from miscommunication between the sexes. Here, he focuses on late twenty and early thirty-somethings, who struggle to strike a balance between business and pleasure.

Alison Scott (Heigl) is a floor manager at a TV station. Out of the blue, her boss Jack (Tudyk) lets slip that there are plans to put her in front of the cameras.

Alison celebrates with an alcohol-fuelled one-night stand with Ben (Rogen) - only to find out later she is pregnant.

To the amazement of his wastrel roommates, Ben vows to do the right thing and support Alison. Opposites eventually attract, but not before Apatow has hauled his couple over the coals.

The 129-minute running time is excessive, but Knocked Up blends superlative writing and performances with assured direction and some genuinely touching moments amidst the filthy-minded humour.

OUR RATING: Four out of five stars

Comedy/Romance. Seth Rogen, Katherine Heigl, Leslie Mann, Paul Rudd, Jonah Hill, Jason Segel, Jay Baruchel, Martin Starr, Maude Apatow, Iris Apatow, Alan Tudyk, Kristen Wiig. Director: Judd Apatow.