Daniel Radcliffe reveals reason he quit smoking

Daniel Radcliffe has revealed the reason he quit smoking after two decades.

The Harry Potter star had smoked cigarettes "pretty heavily" for two decades before finally ditching the habit thanks to a self-help book.

Asked whether there was a habit or substance he was hoping to quit, Daniel, 36, told New York Magazine he had recently stopped smoking, having taken up the habit in his teens when he was still starring in the title role of the Harry Potter movie franchise.

"I have just quit smoking - not 'just' anymore, but I'm going to talk about it, because I would like to mention this book to anybody else who's interested in quitting smoking," he told the outlet. "I smoked for 20 years pretty heavily."

Daniel explained he had found the motivation to give up cigarettes after the birth of his son, whom he shares with girlfriend Erin Darke, when he began having "intrusive thoughts" about his own mortality.

"I was never even thinking about quitting, and then shortly after having my son, the intrusive thoughts of my own death really helped as an incentive to quit," the Kill Your Darlings actor shared.

"I was given this book that I had been told about many, many years ago, called The Easy Way to Quit Smoking, by Alan Carr. It may not work for everybody, but it really worked for me."