‘How I Met Your Mother’ Actor Jason Segel Wrote A Children’s Book Called ‘Nightmares’

How I Met Your Mother alum Jason Segel is now a published author. The actor's first children's novel titled Nightmares! officially went on sale today and is based on the 34-year-olds' real-life childhood nightmares.

"I had a recurring nightmare about witches eating my toes," Jason told Jimmy Fallon on The Tonight Show with Jimmy Fallon when asked about his inspiration.

Jason teamed up with New York Times bestselling author Kirsten Miller to create the middle-grade book that is the first in their planned trilogy. The tale follows a boy named Charlie and a group of other kids that must face their fears in order to save their town.

According to the publisher (Random House) Charlie has lots of problems. "His dad married a woman he is sure moonlights as a witch. He had to move into her purple mansion, which is NOT a place you want to find yourself after dark [and] he can't remember the last time sleeping wasn't a nightmarish prospect. Like even a nap," they wrote.

According to USA Today, at the BookExpo America in June, Jason talked more about his inspiration for the novel and admitted that by writing this book it pushed "my adorability ratings up 1,000 percent ... My mother thanks you."

While promoting his book on the Today show this morning the Sex Tape actor talked about fear, being brave and bad dreams.

"It's okay to be afraid," Jason explained to Matt Lauer during his interview. "I'm not afraid to be bad at something until I'm good at it."

He continued, "I think that your dreams are sort of manifestations of an energy that you haven't dealt with. So I started dealing with them creatively."

Jason added in a couple of life lessons before leaving the show.

"You know what I learned as I got older? To give myself a break," he said. "As long as I'm trying as hard as I can ... you're going to mess up and you're not going to be perfect. It's OK. Everything's OK."

Nightmares! is now available in bookstores and online.