(Adds ratings slump)
By Piya Sinha-Roy
LOS ANGELES, April 29 (Reuters) - Fox's hit animated show "The Simpsons," which has used donut-loving Homer and his dysfunctional family to satirize U.S. popular culture for 25 years, is celebrating another milestone with a plastic makeover featuring Lego building blocks.
"Brick Like Me," airing on Sunday, marks the show's 550th episode and adds a notch in this year's revival of the popular Danish plastic building brick, after the runaway success of February's "The Lego Movie."
"The Simpsons," created by Matt Groening and premiering in 1989, has rarely changed its basic visual form in a quarter century. It is the world's most-watched U.S television show, syndicated across more than 100 countries, and reaches more than 150 million viewers a week according to Fox. The show also has one of the largest TV Facebook fan pages with 72 million.
The show has tapped into the changing American zeitgeist and successfully embedded itself in international pop culture over the past two decades, with Homer's "D'oh!" catchphrase entering the Oxford English Dictionary in 2001.
"Brick Like Me," the brainchild of longtime "Simpsons" writer-producers Brian Kelley and Matt Selman, will see both the cartoon characters and town of Springfield reimagined in the form of the plastic toy brick blocks.
In a clip of footage shown to Reuters, Homer and Marge wake up in their 3D Lego forms and Homer tumbles, disassembling himself. Later, Bart goes to Springfield Elementary school and manages to reduce the building into a rubble of plastic bricks.
"We really try to take full advantage of the Lego playground, to tell the story from a different way than we usually would," Selman said at the show's headquarters in the center of the Fox Studios lot in Los Angeles.
"It yielded a ton of jokes being able to be in a world that is similar to our normal universe but different in key ways," Kelley said. "It's very hard on the regular show to disassemble our characters without causing them permanent harm, but in Lego, we could do that," he added.
"The Simpsons" has endured in part due to its ability to mirror and comment on cultural and social issues through the average middle class American family of Homer, Marge and their children Bart, Lisa and Maggie. The show often fuses classic family themes with pop culture references.
"We do a parody of a current movie series in this episode, but it's always a goal that the show be timeless as it can be," Kelley said. "If there's too many pop culture references, it can really date the show."
FINDING FRESH STORYLINES
Al Jean, executive producer of "The Simpsons" and one of the original team from 1989, said viral content - including an animated parody of Ellen DeGeneres' recent Oscars selfie that showed Bradley Cooper kicking Homer out of the frame - had always helped keep the show current.
Once able to draw upwards of 12 million viewers per episode a decade ago, the current "Simpsons" season has averaged 6.1 million viewers per episode. The ratings slump did not concern Jean, who said the show was still in the top five primetime scripted shows commanding the highest advertising rates.
After 25 years, Jean said the biggest challenge he and the writers faced is finding fresh takes on some storylines.
The writing team gather around a large rectangular wooden table in a room with high ceilings and wooden beams. On one wall, large square placards featuring the show's characters have been signed by the show's eclectic guest stars.
Selman said that while the show doesn't rely on guest stars, he'd like to see Sean Connery and David Bowie lend their voices, while Jean said he'd like to see comedian Will Ferrell.
As season 26 goes into production, fans can prepare for the big episode where a character will die - the only clue Jean gave is the character's voice actor has won an Emmy for the role.
But one beloved "Simpsons" figure was forced to retire in the 25th season - Springfield Elementary's jaded teacher Edna Krabappel, voiced by late actress Marcia Wallace.
Wallace's death in October 2013 raised questions about the show's future if any of the lead voice actors - Dan Castellaneta, Nancy Cartwright, Julie Kavner, Harry Shearer, Yeardley Smith and Hank Azaria - left the show.
"The short answer is we don't want to do it without our cast, and the longer answer is, I wouldn't want to think about or project on that," Jean said.
(Reporting by Piya Sinha-Roy; Editing by Tom Brown)