Eric Bana found his Funny People co-stars so amusing he was given a nickname on set: the giggle monster. The Aussie actor returns to his comedy roots in the latest movie by director Judd Apatow (The 40 Year Old Virgin, Knocked Up) about a group of stand-up comedians. True to its title, the movie stars some of the funniest people in Hollywood, including Adam Sandler, Seth Rogen, Jonah Hill and Leslie Mann, who is married to Apatow.

It was Mann who bestowed the title `Giggle Monster’ on Bana when he struggled to contain his mirth.

“He would laugh every time Leslie was serious,” Apatow said during a visit to Australia to promote Funny People. “My wife is very funny but in ways she does not understand, so when she’s acting very serious it looks kinda crazy, and he would laugh a lot. There was one moment where, in the middle of a take, he kept laughing so Leslie, in character, slaps him in the face. But really I think she just wanted to hit him so he would stop laughing.”

Australians may fondly remember Bana as the mullet-headed Poida, but in recent years Bana has made a name for himself internationally for dramatic roles in Munich, The Other Boleyn Girl and Star Trek.

Funny People is his first foray into comedy in many years – though he was name-checked in a joke in Knocked Up. Apatow said he was impressed when he watched some of Bana’s early work on sketch comedy shows like Full Frontal and The Eric Bana Show Live.

“I always thought his story was very interesting, that he started out doing stand-up and sketches and became this serious actor,” Apatow said. “So when we were thinking about who could play the part we remembered that we goofed on him in Knocked Up and we thought maybe that’s a perfect way to go. We were looking for an original take on an obnoxious businessman.”

It was Bana’s idea to make the character an Aussie, and it’s the first time he has been able to use his real accent on a movie in about 10 years.

But it was Apatow who suggested they use Bana’s obsession with AFL club St Kilda for some laughs.

“I just asked him what are you interested in and I’ll put that in the movie and he said `I love footy’,” Apatow explained. “He is obsessed with footy, if his team loses he cries, and he’s proud of the fact he cries. So I said, `that’s hilarious’. I don’t think he ever understood why I thought it was funny, because he takes it very seriously.”

Funny People will be released nationally on September 10.