Melissa McCarthy is to star in the sequel to Judd Apatow's Knocked Up.

The Bridesmaids actress will join Leslie Mann and Paul Rudd, who return as troubled couple Pete and Debbie in Turning 40.

According to The Hollywood Reporter McCarthy will play a mother whose son attends the same school as the pair's children.

It is rumoured that Ryan Lee the star of Super 8 will play her son.

Apatow, who is directing the feature, tweeted on July 1: "Four days into the shoot. It feels like the last few days of shooting apocalypse now. I am suicidal in the silver fish. Seems funny though."