Zac Efron celebrated his 26th birthday with Robert Pattinson and Joe Jonas in the Chateau Marmont in West Hollywood on Friday night (10.18.13).
But the 'That Awkward Moment' star - who completed a stint in rehab earlier this year for alleged cocaine and alcohol abuse - avoided the temptation to party in favor of a quiet dinner with a group of friends and his brother Dylan, 21, before acting as their designated driver afterwards.
Earlier in the day, the former 'High School Musical' star played a round of golf in Carlsbad, California, where he worked out between shots doing push ups on the course, according to JustJared.com.
Zac recently credited his family for keeping him grounded and helping him to stay sober.
He said: "My family's my rock. I know that they're not going anywhere. More and more I rely on my little brother to keep me grounded. He's 21 now."
The 'Parkland' star also relies on his close circle of friends when he can't turn to his family.
He added: "I know my family's always going to be there, and then there's also some times when life changes, they can't always be there for you in the way that you need, so I rely on my friends."