The couple announced their debut children’s book Hattie Harmony: Worry Detective, which will be published by Viking Children’s Books on June 28, 2022

On Thursday, the couple announced their debut children’s book Hattie Harmony: Worry Detective, which will be published by Viking Children’s Books on June 28, 2022.

“Robbie and I couldn’t be more thrilled to introduce the world to Hattie Harmony,” the 32-year-old WandaVision actress tells PEOPLE in an exclusive statement. “Inspired by the picture books we adored as kids, we hope that Hattie will become a friend and a welcomed reminder to be kind to yourself and to each other.”

She continues: “We couldn’t have brought Hattie’s world to life without Marissa Valdez’s imaginative illustrations. In the words of Hattie Harmony… ‘Worry, Worry, Go Away… There’s No Time For You Today.’ ”

Hattie Harmony: Worry Detective is the first book in the couple’s new series. Illustrated by Marissa Valdez, the picture book follows Hattie Harmony, a “Worry Detective,” who helps her friends overcome their everyday anxieties like getting on the school bus or speaking in front of their classmates. With sweetness and warmth, she also finds ways to deal with her own fears.

“When we sat down to write Hattie Harmony, our goal was to create a relatable character who made talking about complicated feelings fun and engaging for kids,” Olsen and Arnett, 29, explain in a joint statement.

“We hope Hattie Harmony will become a welcomed reminder that it’s okay to speak up when we need help,” they continue, “and to always treat ourselves and others with kindness.”

The pair made their first public appearance as a couple in September 2017. Olsen is loved by Marvel fans for her portrayal of Wanda Maximoff and Arnett is a lead singer in the indie band Milo Greene. Now, they’re joining creative forces to teach children about wellness.