methyl has a good point... deffinition of 'famous'... if it's the most widely known, here in the U.S. it would likely be Charles M. Schulz . What? Never heard of him? He's the artist that originated the "Peanuts" (a/k/a/ Charlie Brown) cartoon series... one site testifies: "... beginning on October 2, 1950, to February 13, 2000 (the day after Schulz's death). In total 17,897 different Peanuts strips were published. The strip was one of the most popular and influential in the history of the medium, and considered the most beloved comic strips of all time. It was "arguably the longest story ever told by one human being,'"' according to Professor Robert Thompson of Syracuse University..."
Far more prolific than any of the "artists" usually thought of when this question is asked...