Prince George, Princess Charlotte and Prince Louis will play a significant role in King Charles' coronation.
The siblings are expected to join their parents, the Prince and Princess of Wales, in a carriage behind the monarch and the Queen Consort Camilla for the coronation procession at Westminster Abbey on May 6 (local time).
George, nine, Charlotte, seven, and Louis, four, and their parents, will be joined in the procession by the Princess Royal, her husband Vice Admiral Sir Tim Laurence, the Duke and Duchess of Edinburgh, the Duke and Duchess of Gloucester and Duke of Kent and Princess Alexandra, according to The Times newspaper.
It is believed that the Duke and Duchess of Sussex are not expected to participate. The plans also show no roles for Prince Andrew or his daughters Princess Beatrice and Princess Eugenie.
Charles' coronation will fall on a Saturday (local time) and the following day, Windsor Castle is set to host a concert that will be broadcast around the world, with thousands of street parties in the afternoon across the UK.
The ceremony will start with Camilla being crowned, before Charles is officially made monarch by the St Edward's Crown being placed on his head by the Archbishop of Canterbury.
A procession will lead the King – who is to be anointed with vegan holy oil – past thousands of people to Buckingham Palace, where he will join members of the royal family on the balcony to wave at fans.
The plans follow reports last year Charles was intent on having a "slimmed down" coronation compared to his late mother's, when 8251 people squeezed into Westminster Abbey to mark her ascension to the throne.