 And, in 1998, Allen and Meadows guest starred in an episode of "".Allen did voice work in two episodes of "The Simpsons" in the 1990s, appearing once as the electronically "altered" voice of Bart Simpson in season 3's "Separate Vocations", and as himself in season 6's "'Round Springfield".Allen was a comedy writer and author of more than 50 books, including several volumes of autobiography; children's books; a series of mystery novels; and numerous volumes of essays and opinions.