Actor Zac Efron quietly completed a course of rehab five months ago, according to reports Tuesday.

"I'm good, real good," he said at the recent Toronto International Film Festival premiere of his upcoming film, "Parkland," according to E! News, which reported that he had dealt in rehab with alcohol-related issues.

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People magazine later said it had confirmed the E! story., however, reported that Efron's issues stemmed from cocaine and a form of Ecstasy known as Molly. The site added that his problems seriously affected his work on the Seth Rogen film "Neighbors" during shooting in April, when he missed several days on set.

Efron's spokeswoman told Newsday that she would not be making a comment at this time.

Efron, 25, who rose to fame as a star of the 2006 Disney Channel TV-movie "High School Musical" went on to films including "Hairspray" (2007), "17 Again" (2009) and "The Lucky One" (2012). In "Parkland," an ensemble drama about the assassination of John F. Kennedy, he plays real-life doctor C. James Carrico, the 28-year-old first-year surgical resident who was the first to examine the fatally wounded president at Parkland Memorial Hospital in Dallas. Carrico, who passed away in 2002, remained at Kennedy's side for 25 minutes until a colleague pronounced the president dead. The movie's cast also includes Tom Welling, Paul Giamatti, Billy Bob Thornton and Marcia Gay Harden.

Efron, who dated his "High School Musical" co-star Vanessa Hudgens for about three years before breaking up in December 2010, has not previously been the subject of widespread reports of substance abuse.