The citizens of Springfield (wherever it may be) will get a visit from a very famous pop star when Lady Gaga stops by 'The Simpsons' on Sunday night for the show's 23rd season finale.

She may be a huge celebrity, but Mother Monster was nervous about her guest spot, citing an enormous respect for the show and its producers and writers, but she said the "incredible" script made it easy for her to sign on.

“I come to Springfield on a train with huge shoes on it and I come make the people of Springfield happy for a moment," she said of the episode's plot line. "Along the way, I run into Lisa. I decide it’s my mission to pull Lisa out of her slump.”

'Simpsons' creator Matt Groening said Gaga was terrific to work with (take a look below) and so funny that “we ruined many takes by laughing out loud.”

What else can you expect to see? Costume changes. A lot of them. Gaga's cartoon likeness will sport almost 20 different outfits, and at one point she'll sport hair even taller than matriarch Marge's trademark skyhigh blue 'do.

The Lady Gaga episode of 'The Simpsons' will air Sunday, May 20, on Fox.