The Simpsons Casts Kristen Bell as Marge Simpson for Season 33 Musical Episode

The upcoming season 33 premiere of The Simpsons will kick things off with 'the most musical [...]

The upcoming season 33 premiere of The Simpsons will kick things off with "the most musical episode we have ever done," according to the series' producers. Part of that? They have cast Frozen and The Good Place star Kristen Bell as the singing voice of Marge Simpson. Apparently the episode will have a lot of singing for Marge to do, as she flashes back through times in her life when she would have had occasion to sing. There seems to be something afoot, since audiences have heard Marge (Julie Kavner) sing before, and she Marge. One of the series' producer say the voice is "different, let's say." Hmm...!

Titled "The Star of the Backstage," the episode is set to premiere on September 26. Executive prouducer Matt Selman describes it as "like a Broadway musical of an episode with all original songs."

"Marge has amazing memories of being the stage manager of her high school musical, Y2K: The Millennium Bug, and decides to restage it with everyone 20 years later for one last show," Selman told Entertainment Weekly after the episode was announced at this weekend's Comic-Con @ Home. "But when her old high school nemesis comes to town, she realizes that her high school memories aren't what she thought they were."

He added, "The only place Marge sang beautifully was in her head, so she has a magical inside singing voice that only we can hear. When she sings, it comes out beautiful, like Kristen Bell."

You can see the panel below.

EW explains that the episode was inspired by the concept of Disney+ reality series Encore, which Bell hosted -- a tie-in that is likely to make some fans of The Simpsons bristle, since each new instance of using the show to promote Disney's corporate priorities tends to set off waves of online groans.

"The Star of the Backstage" was written by Simpsons writer-producer Elisabeth Kiernan Averick, who previously served as a writer and producer on Crazy Ex-Girlfriend. She co-wrote the lyrics with that show's composer Jack Dolgen, who wrote the music for this episode.

That series' creator and star, Rachel Bloom, will also appear in a sequence in this year's "Treehouse of Horror" special, which will feature five segments, rather than the usual three.

The Simpsons airs on Sunday nights on Fox. "The Star of the Backstage" is set to premiere on September 26 at 8 p.m. ET/PT.