Grey's Anatomy star Patrick Dempsey has quit smoking on the eve of the launch of a new cancer treatment centre he has funded in his home town.

The actor has donated $250,000 of his own money to a new cancer centre at the Central Maine Medical Center in Lewiston, Maine.

And, as he planned to cut the ribbon on the new Patrick Dempsey Center for Cancer Hope and Healing on 31 March (08), the actor decided it was time to stop smoking. And he’s already a fervent anti-smoker.

The 42-year-old says, "The thought of smoking now is absolutely ridiculous and I think more people have to quit smoking.

"There was a defining moment (for me); I remember being outside and I took a puff and I was like, ‘You know what, it doesn’t taste good anymore to me. This is not what I want to do, and it stopped."