Zac Efron wanted to challenge himself after 'High School Musical'.

The 34-year-old actor rose to fame as Troy Bolton in the Disney trilogy and revealed that he has wanted to take on acting roles that people may not have expected as his screen career has progressed, as shown in his latest film 'The Greatest Beer Run Ever'.

Zac told the Metro newspaper: "I'm constantly faced with two paths. The road that leads to something everybody has already seen or is expecting, or the more challenging road, which tends to be a bit more confusing and definitely the harder road to take. And inevitably I always go with that road when I can."

'The Greatest Beer Run Ever' tells the story of former Marine John 'Chickie' Donohue, who made a mad dash to Vietnam in 1967 with a holdall of beers to support his friends fighting in the Vietnam War and Efron was drawn in by the outlandish story.

Zac said: "He was purely motivated with good intentions, to lift up his friends, and the only feedback he seemed to be getting was probably negative.

"I think that everyone thought he was crazy for doing it. So I love that he just stuck to his own guns and went out there and became somebody that his friends could rely on. It was a tremendous, tremendous feat."

Efron explained that he enjoyed the blend of humour amid the backdrop of the seriousness of the Vietnam War.

The 'Gold' actor said: "I love the seriousness of the subject matter, and I also love the balancing act of finding the humour and the moments of humanity in this crazy, crazy time in American history... it's all sort of this moving puzzle that is really fun."