Los Angeles: Actor Zac Efron`s friends are worried that the Disney star might die like `Glee` actor Cory Monteith.
Friends were stunned when news broke that Efron had completed a stint in a rehab facility, reported Radar online.
"Friends are genuinely worried about him, because if Zac relapses like Cory Monteith did he`ll likely go back to using the same amount of drugs he was doing before rehab," a source said.
Monteith, 31, was found dead in his Vancouver hotel room on July 13 of a heroin and alcohol overdose.
Efron had a near miss in 2011 when his friend Nickelodeon actor Ryan Rottman was arrested for a DUI with Efron and Rumer Willis in the car.
"And it will kill him Zac had been on a downward spiral since 2011, he was just good at hiding it and not getting caught. He was partying because he was unhappy.
"When Rottman got the DUI Zac was in the car with him and he knew how lucky he was that he wasn`t driving at the time," the source added.
Initial reports stated that Efron attended rehab for alcohol abuse, whereas others have stated he also struggled with using cocaine.