Is Tyler Posey Dating THIS Costar?!

Well, well, well... what do we have here???
Last night at Variety's Young Hollywood party, Tyler Posey couldn't help but gush about his mysterious new girlfriend while chatting with E! News -- and we think we know just who he was talking about!
Of the blossoming romance with an unknown lady, the MTV star said:"It's fresh. It's so fresh. It's not like a secret or anything. It's just pretty new....[But] I'm happy."
The 25-year-old added of the person he said he met while filming a recent project:"