Serena Williams is adding another title to her résumé: children’s book author. 

The tennis star and 23-time singles Grand Slam champion wrote “The Adventures of Qai Qai” based on her daughter’s favorite doll. The children’s picture book, published by Macmillan imprint Feiwel and Friends, will come out Sept. 27, 2022.

The story follows the...

Serena Williams is adding another title to her résumé: children’s book author. 

The tennis star and 23-time singles Grand Slam champion wrote “The Adventures of Qai Qai” based on her daughter’s favorite doll. The children’s picture book, published by Macmillan imprint Feiwel and Friends, will come out Sept. 27, 2022.

The story follows the character Baby Girl as she worries about a coming dance recital. Her doll Qai Qai comes to life and the two embark on “a magical journey that shows Baby Girl that she’s ready for the stage,” according to the book’s description. The book is illustrated by Yesenia Moises, an illustrator and designer. 

‘The Adventures of Qai Qai’ is slated to be released on Sept. 27, 2022.

Photo: MACMILLAN

“Storytime is such an important pillar of our bedtime routine, like so many others around the world,” Ms. Williams said in a statement. “Qai Qai is a special member of our family and we hope ‘The Adventures of Qai Qai’ will give others a new way to welcome Qai Qai into their home.”

Representatives for Ms. Williams didn’t immediately respond to requests for comment.

Ms. Williams and her husband, Alexis Ohanian, welcomed their daughter Alexis Olympia in 2017. Olympia’s doll Qai Qai has since become something of an internet celebrity, with more than 350,000 followers on Instagram and more than 25,000 on Twitter. An animated version of the doll, designed by entertainment technology company Invisible Universe Inc., performs dances and poses for photos on social media. Qai Qai dolls are also sold online.

Invisible Universe is publishing the book with Ms. Williams, who is a partner and investor in the company.

Throughout her career, Ms. Williams has built ventures off the tennis court, including her own clothing line, venture-capital firm and philanthropic pursuits. Ms. Williams previously published a memoir titled “On the Line” in 2009. She and her sister, fellow tennis star Venus Williams, recently served as executive producers on “King Richard,” the 2021 film starring Will Smith about the role their father played in their success in the sport.

Write to Jennifer Calfas at jennifer.calfas@wsj.com