The two future monarchs are to take to the stage to pay public tributes to the Queen during the Jubilee concert on Saturday evening.
The Prince of Wales and the Duke of Cambridge will speak separately in honour of the monarch towards the end of the BBC’s open-air show, which will be staged in front of Buckingham Palace.
A number of celebrities including Diana Ross, Alicia Keys, George Ezra and Eurovision 2022 runner-up Sam Ryder will entertain a live crowd of 22,000 people and a television audience of millions.
Clarence House and Kensington Palace announced both Charles and William would address the crowds at the Platinum Party at the Palace, which falls on the third evening of the four-day Jubilee festivities.
It is not known whether the Queen will attend the concert.
The Queen, who has been facing ongoing mobility problems, pulled out of attending the service of thanksgiving at St Paul’s Cathedral on Friday after experiencing discomfort following two balcony appearances and a beacon lighting on Thursday.
Nearly 50 members of the royal family including the Duke and Duchess of Sussex joined in honour of the absent head of state for the religious occasion.