George R. R. Martin used to be a big Marvel comic fan before he started writing A Song of Ice and Fire series. Martin was such a big fan that he wrote to Stan Lee about how much he was into the franchise.
In an interview on Superheroes Decoded: The Thing by the History Channel, Martin reads an excerpt from a fan letter he wrote to Marvel about Fantastic Four #17.
“Dear Stan and Jack [Kirby, fellow Marvel overlord],
F.F. #17 was greater than great. It will live forever as one of the greatest F.F. comics ever printed, ergo as one of the greatest of all comics. In what other comic mag can you see things like a hero falling down a man-hole and a President of the U.S.A. leaving a conference that may determine the fate of the world to put his daughter to bed… Then there’s your cover boast ‘The World’s Greatest Comic Magazine’ and by gumbo, you achieved it! If you were only half as good as you are now, you’d still be the world’s best mag.
George R. Martin.”
Stan Lee even responded to his letter, writing back to him “We might as well quit while we’re ahead. Thanks for your kind words George.”