The Duke and Duchess of Sussex have posted an adorable new photograph of baby Archie Harrison today - showing his feet as Meghan, 37, celebrates her first mother's day with her son.

The adorable single image shows the newborn's two tiny wriggling feet being gently held by the Duchess of Sussex's hand, with forget-me-nots - Harry's mother Princess Diana's favourite flower - clearly visible in the background.

The photograph and accompanying caption celebrates Mother's Day, which is being marked in the US and other countries around the world today, and is believed to have been taken at the couple's new home, Frogmore Cottage in Windsor.

View this post on Instagram

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. Quote from “lands” by @nayyirah.waheed: my mother was my first country; the first place i ever lived. Photo © SussexRoyal

A post shared by The Duke and Duchess of Sussex (@sussexroyal) on May 12, 2019 at 6:21am PDT

Buckingham Palace has confirmed to MailOnline that the photograph features Archie and the Duchess of Sussex.

It's thought that Meghan also penned the caption, as some have pointed to the American spelling of the word 'honor', which in British-English is spelled 'honour'.

Britain's Prince Harry and Meghan, Duchess of Sussex, joined by her mother, Doria Ragland, show their new son to Queen Elizabeth II and Prince Philip at Windsor Castle. Photo / AP

Accompanying the image of Archie's ten toes, which are wrapped in a pristine woollen blanket, is the message: "Paying tribute to all mothers today - past, present, mothers-to-be, and those lost but forever remembered. We honour and celebrate each and every one of you."

The heartfelt missive continues: "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."

The Sussex Royal account also quotes a poem Lands, by Nayyirah Waheed, in the caption of the sweet image.

Britain's Prince Harry and Meghan, Duchess of Sussex, during a photocall with their newborn son. Photo / AP

The picture also clearly shows a striking flourish of forget-me-nots, which have long held a special place in Harry's heart.

Forget-me-nots featured in Meghan's bouquet on the couple's wedding day, as a tribute to Harry's late mother Princess Diana, who loved the small purple flowers.

The Duke of Sussex hand-picked several flowers from their private garden at Kensington Palace a day ahead of the wedding.

The Duke and Duchess of Sussex showed the world their new son Archie Harrison from St George's Hall at Windsor Castle. Photo / AP