The book, titled "The Bench," is "about the special bond between father and son -- as seen through a mother's eyes" and will be released on June 8, a press statement said Tuesday.
"Inspired by her own husband and son, The Duchess of Sussex's debut touchingly captures the evolving and expanding relationship between fathers and sons and reminds us of the many ways that love can take shape and be expressed in a modern family," the statement said.
"The Bench started as a poem I wrote for my husband on Father's Day, the month after Archie was born," Meghan, The Duchess of Sussex, said. "That poem became this story."
Meghan added that award-winning artist Christian Robinson provided watercolor illustrations for the book, designed to show the "warmth, joy, and comfort of the relationship between fathers and sons from all walks of life."
"This representation was particularly important to me, and Christian and I worked closely to depict this special bond through an inclusive lens," Meghan said.
The book will be 40 pages long and is meant for children aged 3-7.
"My hope is that The Bench resonates with every family, no matter the makeup, as much as it does with mine," Meghan added.
In February, Meghan and Harry announced that they are expecting their second child.
The Sussexes stepped back from the royal family last year, giving up their royal titles and saying at the time that they wanted to be financially independent.
The couple relocated to Meghan's hometown of Los Angeles.
Earlier this year they sparked a heated conversation about racism, the British tabloid press and the royal family following their bombshell interview with Oprah Winfrey.