Meghan Markle's children's book 'The Bench' is a No. 1 New York Times bestseller

• Meghan Markle's children's book, "The Bench" became a bestseller within one week of its release.
• The book originated as a poem for Prince Harry and expanded into a fully-fledged picture book.
• "The Bench" was published on June 8 and topped The New York Times' list of children's picture books.

Within a week of being released, Meghan Markle's children's book "The Bench" is a New York Times bestseller.

As Insider previously reported, the picture book is about a father-and-son bond as seen through a mother's eyes.

The book started as a Father's Day poem for Prince Harry but turned into a book filled with "moments of love and shared experiences between a diverse group of fathers and sons," according to Archewell, the organization the Duke and Duchess of Sussex founded in 2020 and named after their first child, Archie.

Markle's book quickly earned its spot as No. 1 on the New York Times' list of bestselling children's picture books. In celebration, a letter was published on Archewell's website thanking readers for their support.

"While this poem began as a love letter to my husband and son, I'm encouraged to see that its universal themes of love, representation, and inclusivity are resonating with communities everywhere," Markle writes in the letter.

"In many ways, pursuing a more compassionate and equitable world begins with these core values," the letter continued. "Equally, to depict another side of masculinity - one grounded in connection, emotion, and softness - is to model a world that so many would like to see for their sons and daughters alike."

The book, which was illustrated by Christian Robinson, was released on June 8 in partnership with Random House Children's Books in the US; Tundra Books in Canada; and Puffin in the UK, Ireland, Australia, New Zealand, India, and South Africa.

Markle started writing the book two years ago in June 2019, shortly after her son Archie was born in May.

The book features watercolor illustrations that aim to resonate "with every family, no matter the makeup, as much as it does with mine," Markle said in a press release.

Throughout the book, readers will spot Harry and Archie feeding family chickens at their home in Montecito, California. Readers will also catch a glimpse of Markle and Lilibet Diana Mountbatten-Windsor, the couple's first daughter who was born on June 4, in the pages of the book.

"Christian layered in beautiful and ethereal watercolor illustrations that capture the warmth, joy, and comfort of the relationship between fathers and sons from all walks of life," Markle previously said.

"This representation was particularly important to me, and Christian and I worked closely to depict this special bond through an inclusive lens."