EXCLUSIVE

The naked Emma Stone photo that has blessed the web is -- unfortunately -- NOT EMMA STONE ... so says Emma Stone.

A pic showing a buck-naked red-haired beauty snapping a selfie in the mirror has gone viral ... and damn if it doesn't look a lot like the "Easy A" actress. Several websites have published the photo -- saying it's definitely Stone.

But a source close to Emma is adamant ... it's just not her.

As for who really owns the bare lady parts? She's yet to come forward.

Up to now, Emma's managed to keep her lady bits covered in the movies ... which is why this photo exploded on the Internet.