The Duke and Duchess of Sussex will join the Queen, the Prince of Wales, the Duchess of Cornwall and the Duke and Duchess of Cambridge at the couple’s final official engagement before they quit royal life.
Buckingham Palace gave further details of Harry and Meghan’s appearance at the annual Commonwealth Day service at Westminster Abbey next week.
It will be the first time the duke and duchess have appeared with the royal family since their bombshell Megxit announcement in January, and their last as senior royals.
Harry and Meghan caused a royal crisis by announcing they wanted to step back into a dual role, supporting the Queen and earning their own money.
But the plan was unworkable, and the couple are now dropping their HRH styles and stepping away from the monarchy completely, for a life mostly in North America, from March 31.
The service in London on March 9 will be broadcast live on BBC One and across the BBC World Service.
International boxing champion and Olympic gold medallist Anthony Joshua will deliver a reflection, while singers Alexandra Burke and Craig David will perform.
Guests of honour among the 2,000-strong congregation will include Prime Minister Boris Johnson, the Commonwealth secretary-general Baroness Scotland, high commissioners, ambassadors, faith leaders and more than 800 schoolchildren and young people.
The Queen and the royal family will meet people involved in the service and walk past the Commonwealth flag bearers as they leave.
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