I've met two, both totally contrasting characters. One was Bruce Forsyth at a London restaurant in 2002 when we somehow got in each other's way in a narrow corridor leading to the Gents - you know when you both intend to avoid each other but move in the same direction, and he looked really nasty and said "Get out of the effing way you dickhead" - charming, thought I. Not a bit like his TV persona. I just wish now I'd given him a mouthful back instead of saying sorry.
The other was Frank Skinner in a pub in Chelmsford, also in 2002 (no idea what he was doing there), but I accidentally dropped a £2 coin and it rolled along the floor. Frank picked it up, handed it to me, and said "here you go mate, don't chuck your money away" in that familiar Brummie accent of his. He was there with a woman - maybe his partner. No idea.