Christopher Mintz-Plasse thinks Zac Efron's fans will be surprised by his performance in 'Bad Neighbours'.

The 24-year-old actor stars alongside the 'High School Musical' heartthrob in the upcoming comedy and has confessed he thinks Efron's fans will be surprised to see how well he suits the genre.

Quizzed on how his co-star Seth Rogen and producer Evan Goldberg pushed the boundaries in the film, Mintz-Plasse told Collider: ''I think the biggest thing that they did in this, or the biggest stretch or biggest person, was Zac because this is the craziest thing he's ever done.

''Him swearing, making d**k jokes and having sex with girls on screen is the craziest thing he's ever done, and I think people are going to see it and at first they're going to be like, 'Oh, hey, it's Zac', and then I think they're going to realise how hilarious he is and how talented he is.''

Mintz-Plasse - who is best known for playing McLovin' in 2007 hit comedy 'Superbad' - admitted that having seen the film, he can't imagine anyone else doing a better job than Efron.

He added: ''He's great in this movie. No one else could have done it.''