I met him one - on accident.
I was working at a hall as a caterer, and there was a connected theater next door. He came in the back door, saw me, and said "Hey kind sir...can I get back stage from here?"
I said "Sorry Mr. Cosby, you have to go next door."
He said "It smells DAMN good in here, I know where I'm comin' after the show!" then walked out.