Meghan Markle and Prince Harry honored Mother's Day by donating supplies to a shelter for pregnant women

• Meghan Markle and Prince Harry donated a year's worth of diapers and supplies to an LA shelter.
• The shelter, Harvest Home, received the supplies as a Mother's Day surprise.
• Markle, who's pregnant, wrote a letter about supporting underserved communities and mothers.

In light of Mother's Day, Meghan Markle and Prince Harry, through their Archewell foundation and in partnership with Procter & Gamble, donated a year's worth of diapers and cleaning supplies to a Los Angeles-based organization that provides housing for pregnant women and their children.

Harry and Markle's Archewell foundation website says the donation will support the organization Harvest Home's first facility, as well as their new shelter, which is not yet open.

Along with their donation, Markle - who's pregnant with the couple's second child, a baby girl - sent a personal letter to Harvest Home.

The organization shared Markle's letter in an Instagram post.

In it, Markle wrote: "As a mom, and an expectant mom, I deeply appreciate the significance of community support, safe and accessible pregnancy resources, and trusted guidance in a nurturing setting. These ingredients are essential to not just our physical health, but our mental well-being, and I commend you for leading a compassionate community that lives these values."

Markle thanked the organization for taking care of "women and mothers who are turned away elsewhere, at no fault of their own."

"When we consider how vulnerable any mother feels during the fragile time of pregnancy, we gain perspective about how especially difficult it can be for pregnant women of color and those who come from under-resourced and vulnerable communities," Markle wrote.

The Duke and Duchess of Sussex on Saturday promoted worldwide COVID-19 vaccination efforts by delivering speeches during Global Citizen's Vax Live benefit concert - a fundraiser which they co-chaired.

Markle's speech focused on the economic hardships that have impacted women, and particularly women of color, during the pandemic.

The duchess also recently announced that she wrote a children's book, "The Bench," which is about the bond between a father and son from the mother's perspective, according to a press release from Random House Children's Books.

Christian Robinson, a Caldecott winner, illustrated the book, which will be released on June 8.

"'The Bench' started as a poem I wrote for my husband on Father's Day, the month after their son, Archie, was born," Markle said in the press release. "That poem became this story."

Last week, Markle and Harry celebrated Archie's 2nd birthday.