Jai Courtney underwent a punishing exercise regime to bulk up for his 'Suicide Squad' role.

Jai Courtney

Jai Courtney

Courtney had to hit the gym non-stop and take on a protein rich diet to beef up to play Captain Boomerang in the forthcoming Warner Bros. and DC Comics anti-hero movie about a mercenary team of super villains.

Speaking to Haute Living San Francisco, the Australian hunk said: "I did a lot of Olympic lifting and heavy circuit work ... a crazy nutritional regimen that included a lot of flesh, a lot of protein.

"It was one of those things that was exhausting at first, for example, getting up and eating oatmeal, chicken breasts, and six eggs the very first thing in the morning."

The regime meant that Jai was able to get up to 230lb for the role and do lots of his own stunts.

The actor loved making the movie because he was able to speak in his native Australian accent and because there was great camaraderie on set.

Jai - who appears in the film with Will Smith, Margot Robbie and Jared Leto among others - told Slash Film: "What I think makes this movie so fun is that there is so much antagonism between them all. We all have our roles to play amongst the group. I definitely pick up the kind of class clown slack at times. Harley Quinn (Margot) has this great line where she says, 'Your village in Australia is missing its idiot. You should call home.' Which is a great line and rings true.

"It's been one of those bizarrely pleasant experiences. It was probably the rehearsal time that we were afforded, I think that meant that there was this period of concentration where we got to trust each other and coupled that with this lucky accident of the group that was assembled. We have just had a whole lot of fun."