Zac Efron, who has admitted to substance abuse issues in the past, opened up further during his time filming Running Wild with Bear Grylls.

Zac Efron Talks Needing A 'Social Lubricant'

Efron, 26, shot to superstardom and heartthrob status after playing a loveable basketball player on Disney’s High School Musical. Following the success of the made-for-TV movies, Efron landed roles in feature films, including 17 Again, Charlie St. Cloud and The Lucky One. The busy work schedule, however, wasn’t what got to Efron – it was what came with the fame that the work brought.

"The challenging part was never the work. That was never it," Efron explained. "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.”

As a way of coping with the overbearing situation, Efron reveals he needed a “social lubricant.” Before long his dependency on it grew. “You spend a lot of time in your house, going crazy and pretty soon you need a social lubricant,” he said. “And once I needed that, it became to go anywhere. It was getting to the point where I was caring less about the work and waiting more for the weekend, you know what I mean, when I couldn't wait to go out and sort of let loose and have fun.”

Eventually Efron began to take stock of how self-destructive his partying ways were becoming and decided to take a step back and reevaluate how he was living his life. “When Monday and Tuesday were difficult to get through, I was like, ‘Oh this is bad,'" Efron told Bear Grylls. "I just really want to never again have to take anything from the outside into me to feel good about my outside, to be comfortable in my present skin."

While filming Neighbors with Seth Rogen last year, an insider said Efron “spiraled out of control,” to TMZ. After a stint in rehab, the actor had reportedly gotten his addictions under control and was much happier. "He's healthy, happy and not drinking," a source told E! News.