BREAKING: If Jason Segel isn’t careful, the writer side of his brain might eclipse the actor side. Segel, whose script work includes The Muppets and Forgetting Sarah Marshall, has just made his first big publishing deal. Random House Children’s Books has acquired Nightmares!, a middle-grade fiction series that Segel will write with bestselling author Kirsten Miller (The Eternal Ones) for the Random House imprint Delacorte Press Books For Young Readers. The deal was made by RHCB president/publisher Barbara Marcus and the Delacorte imprint’s veep and publisher Beverly Horowitz, with Segal’s reps at WME and Abrams Entertainment.

Nightmares! is an adventure story about a group of kids who realize it’s up to them to save their town from fear, which has manifested itself in the form of nightmare creatures that have slipped into the everyday world. At its heart, the series is about kids overcoming their fears. Segel first hatched the premise as a movie project. He wrote a screenplay years ago that subsequently went into turnaround. Segel took it back and reverseadapted it as a book. Don’t be surprised if the script suddenly becomes hot stuff as a movie project that mixes scares with humor. The first book will be published in fall 2014.

This is the first book deal for Segel — who started on Freaks And Geeks and is still starring in How I Met Your Mother — beyond all of the movie roles and work writing music, scripts and producing for the big screen.

“I couldn’t be more excited that Nightmares! has found a home at Random House,” Segel said in a statement. “Ultimately, it’s a story about learning that we can accomplish anything, as long as we are brave enough to try. These are the types of stories that always inspired me.”

Jason Segel has the perfect voice to write for children,” says Marcus. “Nightmares! is inventive, genuine, and relatable to middle-grade readers. We’re thrilled to see Jason’s creative vision translated to the page, and can’t wait to introduce him to the publishing world as a tremendous new talent.”