The 35-year-old `Horrible Bosses` star - who checked into rehab in December 2005 for alcohol and substance abuse - admits he feared the drugs and drink were somehow pivotal to his career.
He explained: "Seven years sober. I`m really grateful. It`s really lovely to be present in my life.
"I was terrified [of beingsober] because, I`m not saying I was a great actor before or a great actor since, but I was terrified that whatever my capacity was as an actor beforehand, however little or large - it would completely disappear.
"I [subscribed] to the notion that to be able to express yourself in an artistic form in life, you have to live in perpetual pain, and it-s nonsense. There`s enough pain in the world."
The father-of-two - who has replaced boozy nights out with yoga and spinning - believes he has "genuinely more fun in life" without the drink.
He also reveals he`s on the lookout for a new girlfriend. Appearing on `The Ellen DeGeneres Show`, he told the host he doesn`t have any specific ideas about who could fill the role.
He said: "I don`t have a type. A human being, you know? I suppose kindness is kind of nice and sexy."