11/20/2008 05:12 am ET Updated May 25, 2011

Inside Zac Efron's 21st Birthday

The star of High School Musical 3: Senior Year celebrated his 21st birthday Saturday with an intimate two-hour dinner party at L.A.'s Pace restaurant with a group of friends and family that included his parents and brother, girlfriend Vanessa Hudgens, HSM3 costars Monique Coleman and Ashley Tisdale, her boyfriend Jared Murillo and pals Michelle Trachtenberg, Amanda Bynes, Brittany Snow and singing sisters Aly and AJ Michalka.

Efron kept it causal in a T-shirt and jacket while Hudgens, 19, who "helped plan the party," a source says, donned a colorful mini-dress. Guests arrived with wrapped gifts, including bottles of liquor for the actor, who can now legally drink alcohol.

Efron and Hudgens left the rustic Italian eatery hand-in-hand just before midnight and disappeared into a waiting car. But the celebration continued at a nearby hotel, where the birthday boy hosted an afterparty with some of his dinner guests.

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