Ashley Tisdale birthday bikini party beach flirting Zac Efron piggy back balloons drinking sunglasses
Ashley Tisdale birthday bikini party beach flirting Zac Efron piggy back balloons drinking sunglasses
Ashley Tisdale birthday bikini party beach flirting balloons drinking sunglasses water balloons cup glass dancing drunk

Ashley Tisdale partied with her High School Musical co-star Zac Efron Saturday in Malibu, celebrating her 26th birthday (she's only a year older than Lindsay!).

Body language experts might say that these two looked like a little more than friends as Ash had her legs wrapped around her BFF Vanessa Hudgen's ex-boyfriend's neck. Hmm ... wonder what 'Nessa thinks about these pix!

Oh, and check out Ashley's birthday dance below ...