Some what similar to the Hopkins/Price stories, but totally off-topic to the OP:
I saw Joe Mantegna on Conan O’Brian once, and he described this time he went out to the movies. As it happened, he was in three of the movies whose trailers ran before the feature started. After the third one, the guy sitting in front of him turned to his wife and said, “Jesus, is Joe Mantegna everywhere?” So Joe leaned forward and whispered in the guy’s ear, “You got a problem with that?”
Another Stephen King factoid (no cite to support it, though, so take it with a grain of salt):
During the writing of It, I’ve heard that he had to stop writing for a while because it was scaring the hell out of him.
I saw an interview with Vernon Wells who played the scarry mohawked Wez in The Road Warrior .
He meekly told the story of the first time he saw himself in a mirror woth full costume and makeup he scared himself.
According to IMDB, the kid in The Shining wasn’t allowed to know he was in a horror movie.
:goes to cite: