Festivities started at Pace, an Italian restaurant in Laurel Canyon, where a bunch of Zac's peeps, Amanda Bynes, High School Musical co-stars Monique Coleman and Ashley Tisdale and Zac's fellow Hairspray alum Brittany Snow showed up bearing gifts for their buddy.

After the restaurant closed, a few friends went back to the Chateau Marmont Hotel to keep the party going.

Click on any photo to see the full gallery including Zac Efron, Vanessa Hudgens, Ashley Tisdale, Amanda Bynes, Brittany Snow, Monique Coleman, Michelle Trachtenberg.



Trying to slip out unnoticed, Zac Efron and Vanessa Hudgens leave after a night out with their buddies to celebrate the highly-anticipated milestone birthday. Woo hoo! Troy Bolton is legal, y'all!

Festivities started at Pace, an Italian restaurant in Laurel Canyon, where a bunch of Zac's peeps, Amanda Bynes, High School Musical co-stars Monique Coleman and Ashley Tisdale and Zac's fellow Hairspray alum Brittany Snow showed up bearing gifts for their buddy.

After the restaurant closed, a few friends went back to the Chateau Marmont Hotel to keep the party going.