And cue everyone complaining about Zac Efron, despite the fact that he was an actor long before High School Musical (he was a child actor and I believe was in at least one episode of Scrubs, IIRC, and he also played a young Simon Tam in certain Firefly flashback scenes). And he's done some good stuff since, no least The Life And Death Of Charlie St Cloud, a recent release, and managed to put his 'Disney days' far behind him. Which is a feat so far achieved by a very few, the only other recent Disney star who's successfully done so is Selena Gomez, with her success as an indie/alt rock musician and with backing band 'The Scene'.
My point is, give the guy a fair chance. He's a good actor, regardless of him starring in a few duds. He's done some serious stuff in the past, and been in some really good roles. So he may well be able to pull this one off well too, assuming the rumours are true. Don't just judge him on what he's done in the past, because that's just being ignorant, and being completely biased and dickish for no reason.