"This was a photo which was taken privately. It is a personal matter and it is unfortunate that this has become public," the representative said in a statement released to TMZ.com.
The National Enquirer first reported the photo's existence, but it has since surfaced on blogs all over the Internet.
The 18-year-old actress is dating Zac Efron, her co-star in the two "High School Musical" TV movies.
Celebrity Breakups and divorces of 2014 [PHOTOS]