Daniel Radcliffe: I was "reliant" on alcohol

(CBS/AP) "Harry Potter" star Daniel Radcliffe has revealed he battled with a secret alcohol problem and is no longer drinking.

The 21-year-old actor tells GQ U.K. that he began to drink too much while filming "Harry Potter and the Half Blood Prince," the sixth movie in the "Potter" film franchise, in 2009.

Pictures: Daniel Radcliffe
Pictures:"Harry Potter and the Deathly Hallows" Premiere

"I became so reliant on (alcohol) to enjoy stuff," he told the magazine "There were a few years there when I was just so enamored with the idea of living some sort of famous person's lifestyle that really isn't suited to me."

"As much as I would love to be a person that goes to parties and has a couple of drinks and has a nice time - that doesn't work for me. I do that very unsuccessfully," he said about his decision to cut out drinking altogether, instead of simply cutting down.

"I'd just rather sit at home and read, or go out to dinner with someone, or talk to someone I love, or talk to somebody that makes me laugh."

Radcliffe adds that sobriety has also helped him become a better boyfriend.

"I'm actually enjoying the fact that I can have a relationship with my girlfriend (Olive Uniacke) where I'm really pleasant and not f------ up totally all the time," he says.

Radcliffe shot to fame aged 11 after he was cast as Harry Potter for the movie adaptations of J.K. Rowling's popular books about a teenage wizard.

Many child actors have struggled to cope with adulthood, but Radcliffe said he was determined to prove that child actors could go on to build long careers.

"If I can make a career for myself after Potter, and it goes well, and is varied and with longevity, then that puts to bed the 'child actors argument,'" he said.

The last movie in the series "Harry Potter And The Deathly Hallows: Part 2" premieres on Thursday.

Check out the trailer of the film below.