Video: How WICKED Inspired Idina Menzel & Her Sister, Cara Mentzel, to Write Their New Children's Book

Tony Award-winner Idina Menzel and her sister, acclaimed writer and teacher Cara Mentzel, have released their new lyrical picture book, Proud Mouse.

The duo appeared on Good Morning America to discuss Proud Mouse, which follows a proud sister learning to find her own way. The book is a follow-up to last year's book, Loud Mouse.

During the interview, Mentzel revealed how Menzel's performance as Elphaba in Wicked helped inspire the new book.

"I spent so much of my life being so proud of her," Mentzel shared. "I always say when she's spinning around with her arms extended singing 'The Wizard & I' but there's more than one moment to be proud of her, especially in that show."

The book follows Cara Lee, a proud mouse who is proud of her big sister, Dee. She is proud of her specially decorated journal. And now she’s proud to become what she’s always wanted to be: a student. But her first day of school is different than she imagined. Everyone keeps comparing her to Dee. But who is Cara Lee? When you have a big sister with such a LOUD talent, how can you find room to shine in your own way?

Complete with gorgeous illustrations and filled with humor and heart, Proud Mouse is a clever tale about celebrating the things that make you YOU and having the confidence to stand loud and proud.

Plus, check out where you can see Menzel and Mentzel at upcoming book signings here.

Menzel also recently released her new album, "Drama Queen," a disco-infused love letter to her fans. Menzel, who describes herself in the new interview as a "children's book writer by day and a disco queen by night," worked on the new album with Nile Rodgers, Justin Tranter, Jake Shears, and more.

Watch the interview here: