The move is part of the final push of what's been an extensive "Simpsons" marketing push to honor the series, which concludes with a January 10 one-hour documentary special on the show directed by Morgan Spurlock of "Super Size Me" fame.
Right before the documentary, "The Simpsons" will air its 450th episode.
"We always knew at the end of the campaign we'd go yellow," said Fox executive vp marketing Joe Earley, who has led the year-and-half campaign. The effort has included on-air scavenger hunts, contests for viewers to create their own posters and "couch gag," and even the "Simpsons" receiving their own postage stamps.
It's rare for a network to put such an extensive marketing effort behind a veteran series. It's not as if "Simpsons" is even Fox's highest-rated program on Sundays (that honor goes to "Family Guy).
"For a show to hit its 20th anniversary in today's universe is such a feat, and it still has such a resonance in the zeitgeist," Earley said. "The show has viewers who have viewed it for three generations. Besides, it's such a creative property that it's fun to come up with ideas for it."
home stretch of its "Simpsons" 20th anniversary celebration


