Billie Joe Armstrong and Megan Fox crack up in ‘This Is 40’ gag reel – watch

Chris O'Dowd and Jason Segel also fail to keep a straight face during filming...

A gag reel from Judd Apatow‘s This Is 40 has appeared online – scroll down and click ‘play’ to watch it.

Premiered on Funny or Die, the video shows cast members including Megan Fox and Billie Joe Armstrong failing to keep a straight face as they deliver their lines. Green Day frontman Armstrong makes a cameo appearance as himself in the R-rated comedy film.

This Is 40 is Judd Apatow’s follow-up to his hit 2007 comedy flick Knocked Up. Alongside Paul Rudd, it stars Apatow’s wife Leslie Mann and the couple’s two daughters Maude and Iris Apatow. Chris O’Dowd and Jason Segel also make appearances.

Last month (December 2012), a deleted scene from the film featuring Armstrong surfaced online – click here to watch it. Another deleted scene featuring Eels frontman E has also emerged and can be viewed here.

This Is 40 came out in the States back in December (2012) and hits in UK cinemas on February 14. The film’s soundtrack features new songs by Fiona Apple, Lindsey Buckingham and Norah Jones.