Upcoming "Simpsons" Guest Stars

Matt Groening will appear on "The Simpsons" on April 18. You can spot him happily signing autographs for fans at a Springfield sci-fi convention in "My Big Fat Geek Wedding." Plus, Anannova reports that Ricky Gervais will pop in on Springfield later. Previously the media reported Gervais had turned down Matt Groening when he offered the job. D'oh!