Gabriel Byrne was on the Actors Studio (Original Airdate) 10 December 2000
The host (James Lipton) asked - "If Heaven exists, What would you like to hear God say when you arrive at the pearly gates?
(Gabriel Byrne) answered - "You see, I do exist"
Video : http://www.vimeo.com/4896336
A further clarification from a British National Secular Society news item (http://www.secularism.org.uk/79004.html), 4/13/07:
"Irish actor Gabriel Byrne has said that he does not believe in God, despite spending five years of his childhood in a seminary training to be a priest.... He says, 'I spent five years in the seminary and I suppose it was assumed that you had a vocation. I have realised subsequently that I didn't have one at all. I don't believe in God. But I did believe at the time in this notion that you were being called.'"