The Knocked Up star, who wanted to quit the ill habit for quite some time now, has apparently not taken a puff for a month, which has boosted her health.
"She feels so much better," the Daily Express quoted a source as telling Us Weekly magazine.
"I don't enjoy it so much now, because I've become such a slave to it. I hate planning my life around when I'm getting a cigarette."
She had decided to quit tobacco in July.