In a statement to TMZ, Hudgens' rep says, "This was a photo which was taken privately. It is a personal matter and it is unfortunate that this has become public." The National Enquirer was the first to report of the photo's existence, and it has since surfaced on various blogs across the net.
Hudgens, 18, is dating her "HSM" co-star, Zac Efron.
ETA: to those who still say it's fake, why would her rep say it's real? it's not really the type of thing you want to make up.
ETA #2:ANOTHER ARTICLE