this is exactly the bit that comes to mind every time i'm reminded of Tim Conway. he's on set with some of the greatest comedic actors of all time and he just destroys their composure with his ad libs.
the first part is the dress rehearsal. The 2nd part is the actual taping....and he changes the story, so they don't know what he's going to say. Vickie Lawrence, who was the youngster of the group and NEVER allowed herself to break, finally breaks for the first time and finishes it off with one of the all-time great bloopers: "Is that little azzhole through?"
He probably doesn't qualify as a "celebrity" but he should, a Medal of Honor recipient, a man who fell on a grenade and survived, Robert Maxwell, dead at age 98. Read this:
RIP Herman Wouk (103!) I woulda guessed he had been dead for years. But he wrote a lot of naval novels and being a Navy man myself I always enjoyed his work,
I like Wouk's work. It's sometimes dismissed as being too soap-opera-y, but I think that's just by people who aren't familiar with those times. Also, it spawned at least one truly horrible movie that may have reflected back on him.