Buckingham Palace has released more details of Prince Harry and Meghan Markle’s final public engagement before they quit as senior royals at the end of March.

The Duke and Duchess of Sussex, and their infant son Archie, are about embark on a new chapter in their lives in North America.

But first, the couple will join the Queen, Prince Charles and his wife Camilla at the annual Commonwealth Day service at London’s Westminster Abbey on March 9.

Harry and Meghan, who announced in January that they would shun the spotlight on the British royals, have not been seen publicly with other members of the royal family for several months, further highlighting the significance of next week’s event. 

Meghan and Harry shared photos on Instagram for St David’s Day on March 3. Photo: Instagram

Also present at March 9 service will be Harry’s brother, Prince William, and wife Kate Middleton.

International boxing champion and Olympic gold medallist Anthony Joshua will deliver a reflection, while singers Alexandra Burke and Craig David will perform.

Harry and Meghan are expected to join the rest of the royal family greeting service participants.

It will be the Sussexes’ final royal duty before they formally step back from the monarchy on March 31 as they attempt to make their new life in Canada. 

The Cambridges and Sussexes at the 2019 Commonwealth Day service. Photo: Getty

Guests of honour in the 2000-strong congregation will include British Prime Minister Boris Johnson, the Commonwealth secretary-general Baroness Scotland, high commissioners, ambassadors, religious leaders and more than 800 schoolchildren and young people.

Tradition dictates that Prince Harry, who is sixth in line to the throne, sits with his wife in the second row of seats behind the Queen, Charles, Camilla, and the Cambridges for the service.

Meghan in Cardiff in 2018, in a photo shared to the Sussexes’ Instagram this week. Photo: Instagram

The Queen and other members of the royal family will meet people involved in the service and walk past Commonwealth flag bearers as they leave.

The Queen’s second son, Prince Andrew, will be absent from this year’s service. He stepped down from public life late in 2019 following a disastrous television interview over his friendship with convicted sex offender Jeffrey Epstein.

-with AAP