The 26-year-old actor gave up alcohol after he finished filming 2011's "Harry Potter and the Deathly Hallows Part 2" because his drinking was getting out of control and says working out helped him to stay sober, reported Female First.
"Like the cliche of anybody who is quitting something, I really got into exercise," he said.
Radcliffe admitted drinking to excess and having to be looked after by friends on more than one occasion.
"I can't tell you what kind of drunk I am because I don't remember what kind of drunk I am. I think I'm probably great - while I'm conscious. But then I have to be looked after and ultimately I don't want to wake up to 20 text messages along the lines of, 'Where are you? Dude, are you OK?'" he said.