Months after completing rehab, actor Zac Efron is opening up about his past struggles with addiction.

The 26-year-old former "High School Musical" star appeared on the first episode of NBC's "Running Wild With Bear Grylls" - a new reality series in which Bear Grylls takes celebrities on a two-day trip into the wild where they participant in challenges to test their survival skills.

While out in the woods, the "Neighbors" actor explained that his problem did not stem from having a heavy work load, but from finding fame at such a young age and becoming too famous.

"The challenging part was never the work," Efron said, according to TheWrap. "It was sort of the in-between work-the social aspects outside of it. I mean, everywhere you go to a certain extent, there is press in some form. Whether you're going to an event where you're supposed to be out...there will be press there, if you're leaving your house to go to the grocery store, there will be press there. It can be everywhere and it can be confusing."

He added: "You spend a lot of time in your house, going crazy and pretty soon you need a social lubricant. And once I needed that, it became to go anywhere."

The actor began seeking out unhealthy coping mechanisms to deal with being in the spotlight. He entered rehab twice last year for undisclosed reasons, but several reports stated that the actor was battling a cocaine and alcohol addiction.

Efron said that his addiction "was getting to the point where I was caring less for the work and waiting more for the weekend, where I couldn't wait to go out and sort of let loose and have fun, but then when Monday and Tuesday were difficult to get through, I was like, 'Oh this is bad."

The actor has rarely opened up about his decision to enter rehab, but he is now believed to be living a sober lifestyle, and said that he meditates as often as possible to help calm his mind.

"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," he said. "It's just meditation and stopping and slowing down your brain."

While on the trip the duo jumped out of a helicopter, ate worms, scaled cliffs, rappelled down a 150 foot waterfall and crawled across a rope stretched between two cliffs in the Catskill Mountains.