Andy Mientus, who has been a theater kid since the fifth grade, took to heart the advice to “write what you know” when he wrote his debut novel, The Backstagers and the Ghost Light (Amulet, Sept.). It’s about a diverse group of stage theater misfits who are whisked away to an alien world, where they have paranormal adventures.

An actor, singer, and songwriter who starred in the Broadway musicals Spring Awakening, Rent, Les Misérables, and Wicked, Mientus has also appeared on television in the NBC musical drama Smash and as the Pied Piper in the CW series The Flash.

When Amulet decided to adapt the Backstagers graphic novel series into a narrative novel format, Mientus says, “somehow, my name came up. I have a comics background. I’ve always been a writer, and I can draw from my own real-life experience of the theater.”

The graphic novels were created by James Tynion IV and Rian Sygh. The latter is staying on with the narrative book project and is illustrating both The Backstagers and the Ghost Light and its sequel.

Describing theater as a “magical” and “fantastical” world, Mientus says it wasn’t difficult to add some “strange creatures and adventure” into the mix to write the novel. While he has no plans to leave the stage for publishing, he does appreciate the art of writing, and compares it to being “playwright, director, and actor” all at once, without having to worry about run times or intermissions.

“I have all the time in the world to take tangential breaks [from the plot] and tell you exactly how [characters] are saying what they are saying. It’s really awesome,” says Mientus.

He hopes to continue writing books, he adds. In the theater, actors spend so much time waiting: either waiting in the wings to go on stage or for the next opportunity to be cast in a play.

“Writing is great,” says Mientus. “Now I don’t have to wait for the next opportunity to be creative: I can be creative on my own.”