Zac Efron has been compared to Cary Grant.

The 27-year-old actor shot to fame in Disney's 'High School Musical' and Andrew J. Cohen, who co-wrote Zac's movie 'Neighbours' says he reminds him of the debonair screen icon.

He told The Wrap: ''He's amazing and so earnest. He gives 150 percent to everything he does and there's something likable and funny about that. Most of the time when he's funny in 'Neighbors,' it's because he genuinely thought he was going to be friends with Seth [Rogen], like when he brings over walkie-talkies. His earnestness is part of his secret weapon in comedy. To me, he's like Cary Grant.''

However, Andrew believes Zac's incredible physique stops people from taking him seriously.

He explained: ''He's the full package and when people underestimate him, it's because they've got six reasons to underestimate him - right below his pecs.''

Andrew and his writing partner Brendan O'Brien have also worked with Zac on the upcoming 'Mike and Dave Need Wedding Dates' and Brendan says Zac has become more confident in his comedic abilities.

He said: ''On 'Neighbors,' even he would admit he was a little nervous about how he was going to fit in with all these people who were such improv maniacs, but on 'Mike and Dave,' he's playing the sweeter, more straight guy and he's hilarious.''