The Cambridges and Wessexes last carried out a joint public engagement together in December 2020 when they thanked volunteers and key workers at Windsor Castle.
WATCH: Royals watch as poppies fall at Festival of Remembrance 2019
While the Queen has had to cancel her appearance at the Festival of Remembrance, her cousins will be present, including the Duke and Duchess of Gloucester, the Duke of Kent and Princess Alexandra.
The monarch, 95, was advised to take two weeks of rest following her hospital stay last month.
A statement released by Buckingham Palace on 29 October read: "The doctors have advised that Her Majesty can continue to undertake light, desk-based duties during this time, including some virtual audiences, but not to undertake any official visits. Her Majesty regrets that this means she will be unable to attend the Festival of Remembrance on Saturday November 13.
"However, it remains The Queen's firm intention to be present for the National Service of Remembrance on Remembrance Sunday, on November 14."
The royal family at the Festival of Remembrance in 2019
The Festival honours the Armed Forces community for their service and sacrifice in defending our freedoms and way of life and commemorates all those who have lost their lives in conflicts.
This year's event marks the centenary of the Royal British Legion and reflects on the different ways the charity has supported the Armed Forces community. The Festival will also commemorate 100 years of the poppy as the symbol of remembrance.
The 30th anniversary of Operation Granby, the largest deployment of UK Forces since the Second World War, will be remembered, and the programme will pay tribute to currently serving members of the Armed Forces who were deployed to Afghanistan as part of Operation Pitting.
The Festival of Remembrance will be broadcast on BBC One at 9pm on Saturday 13th November. To find out more, please visit britishlegion.org.uk
Make sure you never miss a ROYAL story! Sign up to our newsletter to get all of our celebrity, royal and lifestyle news delivered directly to your inbox.