The Hangover Part III star Bradley Cooper has revealed that his co-star Zach Galifianakis is always his first port of call.

The 38-year-old actor, who plays Phil in the comedy film, revealed he leaned heavily on Zach following his father's death in January 2011.

Speaking to Itlay's A magazine, Cooper said: ''Zach is one of my best friends; he's the one I go to when something's wrong. He is the first person I called when my father died.''

The Silver Linings Playbook actor further revealed why The Hangover franchise was so successful, adding: ''I think the reason why everybody likes our characters in Hangover is because we portray real men. We can mess things up, but eventually we all need real friendships.''