Elizabeth Olsen and Husband Robbie Arnett Write Kids' Book About 'Self-Care'

James Wright

Elizabeth Olsen and her husband Robbie Arnett care about wellness — and they want little ones to care about it, too.

On Tuesday, the couple released their debut children's book Hattie Harmony: Worry Detective, which is published by Viking Children's Books.

"Robbie and I couldn't be more thrilled to introduce the world to Hattie Harmony," the 33-year-old WandaVision actress told PEOPLE in December. "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 continued: "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.

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Viking Children’s Books

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"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, 30, told PEOPLE 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 continued, "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.

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"Elizabeth and Robbie brought such empathy and humor to Hattie Harmony, which introduces young readers to the importance of self-care," said Tamar Brazis, associate publisher of Viking Children's Books, in a statement. "This exciting new series provides both parents and kids with useful tools that they can practice whenever they need a little help coming back to the present moment."

Hattie Harmony: Worry Detective is on sale now.