An image was shared on the royal couple’s Instagram on Sunday of Los Angeles-raised Meghan holding the baby’s feet.
It was captioned: “Paying tribute to all mothers today - past, present, mothers-to-be, and those lost but forever remembered.
"We honor and celebrate each and every one of you. Today is Mother's Day in the United States, Canada, Australia, New Zealand, South Africa, Kenya, Japan, and several countries across Europe.
"This is the first Mother's Day for The Duchess of Sussex."
ITV News Royal Editor Chris Ship adds that the picture is not only significant because it marks Meghan's first US Mother's Day, but also the flowers in the background are forget-me-nots, the favourite of Princess Diana, Archie's grandmother.
While Mother’s Day is celebrated in the UK in March, it was held on Sunday in the States, as well as the countries listed on their Instagram account.
The Duchess also quoted from a poem called Lands by Nayyirah Waheed:
my first country;
the first place i ever lived."