Sufjan Stevens’s 2005 album “Illinois” is the source material for a new musical at the Chicago Shakespeare Theater. It’s called “Illinoise,” and it’s the only time you’ll hear us pronouncing the “s” at the end of the state.

“I always felt like there was something to discover in a stage work that derives from this album,” said Justin Peck, the director, choreographer and co-writer behind the show.

Peck identified the album as part of his own coming-of-age story when it came out in 2005, so it’s fitting that he and playwright Jackie Sibblies Drury adapted the record into a coming-of-age tale for the stage. The story is told entirely through music and movement.

In this episode, host Erin Allen talks to Peck for a peek behind the curtain in developing “Illinoise.”