updated 09/19/2013 AT 7:20 PM ET
•originally published 09/19/2013 AT 7:20 AM ET
Zac Efron seemed to have it all.
After he shot to fame at age 17 after starring as squeaky-clean basketball star Troy Bolton on Disney Channel’s High School Musical franchise, it appeared the heartthrob had avoided the pitfalls of youthful stardom.
But after it was revealed Monday that Efron, now 25, had checked into rehab earlier this year, sources tell PEOPLE the seemingly straight-arrow actor – who has never run into trouble with the law and has a sterling reputation as a professional on set – partied much harder than his public image let on.
“He surrounds himself with a group that enjoys partying,” an Efron insider tells PEOPLE. “He got caught up in the partying lifestyle the past few years.”
Says another source who has socialized with Efron: “Like most people at clubs, he liked to drink and have a good time. He definitely liked to party.”
Trying to Avoid the Wrong Path
Just a year ago, the California native – who grew up in a non-Hollywood family (his father is an electrical engineer and his mother a secretary) – told PEOPLE he avoided going down the wrong path by “appreciat[ing] the work I’ve done.”
“The stakes are very high,” he said at the time. “I care too much about those around me and everything I’ve worked for to just go out and blow it. It’s just a personal integrity.”
While acknowledging he does “like to have fun,” the actor pointed out that “some people can handle it and some people can’t.”