After months of keeping mum about the issue, news of Zac Efron's rehab stint has broken out, thanks to the actor's bold attempt to speak up about the issue.

For the first time, the "Neighbors" actor Zac Efron opened up about his two stints in rehab for substance abuse in a recent interview with The Hollywood Reporter.

"I had done films back-to-back-to-back. I was burnt out," Efron said. "There was something lacking, some sort of hole that I couldn't really fill up. I was just so deep into my work, it was really the only thing I had."

"I was drinking a lot, way too much. It's never one specific thing," he continued.

But now that Zac Efron's rehab stint can be put behind him, he shared that he feels less heavy about it now, and admitted that filming "Neighbors" has greatly helped him get back on track.

"Actually, it was a weight off my chest. It was great. It was a fantastic time. It was a rough year,"

"It's kind of funny: Neighbors is such a great icing on the cake for all of this. I was kind of able to channel all of that and put it back into this movie. I feel great. I feel really blessed to be here working with this group of guys. I couldn't be better right now. I'm really excited," he said.

He also developed a fondness for his co-star during filming. In a recent interview with Cleo magazine, Efron can only share nice words for Rose Byrne.

"She might be my favourite actress in the world," Efron admitted.

"She's got like a light about her you can't teach or learn. It's really kinda magical. In this movie she plays a strong, funny, easy-going woman. She's gonna redefine what you want a wife to be."

"Neighbors" opened as the top weekend film in US and Canada beating "The Amazing Spiderman 2" with sales of $51.1M on its first week.