Earlier this year, Justin Bieber challenged Zac Efron to a hair-off.

But before the latter star can take on the world's most beloved 16-year old, Efron has another opponent with whom to deal: himself.

Zac has once again changed up his look, as he showed up on the red carpet of the Charlie St. Cloud premiere with a tussled type of mohawk. This isn't the first time he's surprised fans with a new hairstyle: we asked readers to vote on his contrasting appearances in July of 2009.

Now, we're asking you to do so again...

Which Zac Efron hairstyle do you prefer?