The press only got hold of Efron's rehab troubles months after the fact, but he's finally opened up about his "struggle" in a recent interview with The Hollywood Reporter.
The 26-year-old Neighbors star, who was spotted with an AA chip around his neck last December, said he drank too much alcohol and dabbled in drug use.
"I was drinking a lot, way too much," he said. "It's never one specific thing. I mean, you're in your 20s, single, going through life in Hollywood, you know? Everything is thrown at you. I wouldn't take anything back; I needed to learn everything I did. But it was an interesting journey, to say the least."
"I just started going," he said of Alcoholics Anonymous. "And I think it's changed my life. I'm much more comfortable in my own skin. Things are so much easier now."
Sources told TMZ last year that Efron went to rehab twice because he relapsed on the set of Neighbors. He told THR that while he had fun on set with Seth Rogen, "every single day was more or less a party."
"You went into this kind of dream state: You show up, it's dark, and there's a raging party. Drive home, and the sun's up, go to sleep and then get back to set. Glow lights, girls in bikinis, electronic dance music blasting in between takes, people jumping around. It was pretty cool, but it was a lot. It was a lot. It sort of became real," Efron said.
"It's a never-ending struggle," he added.
"Without those moments where you feel like your lowest, it's impossible to appreciate the high ones," he said. "But I sit here in front of you today much happier and healthier than I've probably ever been."
Notable deaths of 2014 [PHOTOS]