Zac Efron's drug addiction is confirmed, and the actor admitted he needed a "social lubricant" to cope with the pressures of fame.

Zac Efron's drug addiction confession was made in an unlikely venue, in the wild. The "High School Musical" star opened up about his past addiction as the first celebrity guest in NBC's reality show "Running Wild with Bear Gyllis."

The new show takes guests on excursions in the wild, putting their survival skills to the test. It turned out Zac had more to offer than his willingness to jump out of a helicopter, roaming the Catskill Mountains, and eating live grub.

Zac talked about his early rise to fame, and the breaking point which pushed him deep into addiction.

"It was just so quick -- it was shocking. The challenging part was never the work, that was never it. It was sort of the in-between work -- the social aspects outside of it; everywhere you go [there's people watching... and it can be confusing ... and pretty soon you need a social lubricant."

As Zac Efron's drug addiction worsened, he admitted it became more difficult for him to concentrate on work. "Once it became that ... it got to the point where I was caring less about the work and waiting more for the weekend where I couldn't wait to go out and let loose and have fun. But when Monday and Tuesday were difficult to get through, I thought, 'This is bad.'"

Looks like "Running Wild with Bear Gyllis" rubbed on him, gave him another nudge further out of his comfort zone. He says it cost him to recover and come to the point when he could confess in public.

"I just really never again want to take anything from the outside in to feel ... comfortable in my present skin, and that takes a lot of work. It's just meditation and stopping and slowing down your brain." (usmagazine.com)

Zac Efron's drug addiction caused him two stints at rehab and a hiatus in his career.