Idina Menzel is best known for her soaring singing voice and her roles as Elsa in Disney’s Frozen as well as Elphaba in the famed Broadway musical Wicked. Now, in partnership with her sister, Cara Mentzel, an educator and children’s book writer, she’s donning a new title—that of picture book coauthor. The sisters teamed up to write Loud Mouse (Sept. 27), a story about two mouse sisters. Dee loves to sing, but she is anxious about sharing her gift with the world. Cara Lee, her younger sibling, is Dee’s most enthusiastic advocate.

The sisters and coauthors shared their thoughts on writing for children, building confidence, and the mouse characters they based on their own childhood selves.

Tell me about the inspiration behind Loud Mouse.

Menzel: When I was a young girl, I had this voice, this talent that I loved. But I often felt conflicted about sharing it. Sharing my voice with the world, in my case quite literally because it was my singing voice, made me feel both empowered and vulnerable. It opened me up to praise and criticism. And I struggled with my competitive nature, wanting to get the solo, to get the lead part in the show, but not wanting to be the reason someone else didn’t get it. At the most basic level, I had this desire to shine and to be liked.

As I’ve grown older, I’ve realized that we do a disservice to the world when we hide our gifts, our light. That freed me up to experience more of the joy in what I’m doing. So that’s when I called Cara and said, help me speak to young kids about that. Help me write a book about that!

How would you describe the main characters, Dee and Cara Lee?

Mentzel: Well, Dee is based on Idina. I call her Dee, and Dee is a far easier name for a young reader to read! So, you’ll definitely see a lot of my sister in Loud Mouse. She loves to sing. She sings everywhere. She even manages to sing while practicing her math facts—which, let’s be honest, is quite a feat! But when we first meet Dee, she sings only to herself. Cara Lee is her little sister and is based on me. My middle name is Leigh, but again, Lee is a far easier name to read, and the names rhyme, which is also great for young readers. Cara Lee looks up to her sister, thinks she’s just the best singing mouse ever, and provides the wisdom and support that helps Dee untangle her feelings. In real life, we’ve always been close, so you do get to see a lot of that connection in the book, which is special.

What was it like to create a picture book together? What do you feel you each brought to the creative process?

Menzel: It was so fun! It was a really joyful and fulfilling project. Cara is such a gifted writer and teacher—she has her master's in elementary education and literacy. I feel like she’s my street cred. And she just knows how to capture the minds of the kids we’re trying to reach with this story. You know, in some ways, I think I brought the what to the project—what do we want to achieve here? And she brought the how—how do we go about achieving that?

Mentzel: Dee makes it easy. She’s just naturally creative. She’s the one who thought Dee should be La, la, la, LA LOUD. It was also really rewarding to work together as professionals, not just sisters.

Jaclyn Sinquett’s illustrations are a pitch-perfect fit for your story. How did you connect with her? Did you know right away that she was the right illustrator?

Menzel: Aren’t they just perfect! That’s all thanks to our editor, Brit Rubiano, and the rest of the team at Disney-Hyperion. Jaclyn is amazing, and that’s saying a lot because there is tremendous talent in the field. We were pretty awestruck.

Mentzel: We knew right away. She understood the world we were trying to build and not only was she able to deliver that world but also make it better. We also share a similar sense of humor. Honestly, one of the best parts of the experience was getting Jaclyn’s latest drawings, seeing how she interpreted the text, and finding all the thoughtful details she included.

Sisterhood is such a special and unique bond. If you had one message to send to fellow sisters, what would it be?

Mentzel: I’ve given this a lot of thought; my last book was about sisterhood. All relationships are unique, even the ones between sisters. But for Dee and me, being a sister is about being a protector, a cheerleader, and a truth-teller. I think Dee would agree that when it comes to each other, we’re both really good at that.

Menzel: Ooh, well said!

What do you hope readers take away from Loud Mouse?

Menzel: We hope that Loud Mouse helps readers be their brightest, boldest, bravest, loudest selves. It’s true, putting yourself out there is a risk, but do it anyway.

Can we expect more books?

Menzel: We have a good feeling about it.

Metzel: Yeah, you haven’t seen the last of Dee and Cara Lee.