Ten of Queen Elizabeth's great-grandchildren will take part in a pageant at the Royal Windsor Hose Show.
As part of the 96-year-old monarch's platinum jubilee celebrations, the Duke and Duchess of Cambridge's three kids, Prince George, eight, Princess Charlotte, seven, and Prince Louis, four, will ride in a horse-drawn carriage for the Gallop Through History gala performance on 15 May, the Sunday Times newspaper reports.
The trio will be joined by the Queen's eldest great-grandchildren, Peter Phillips and ex-wife Autumn's daughters Savannah, 11, and Isla, 10, and Zara and Mike Tindall's trio, Mia, eight, Lena, three, and 13-month old Lucas.
In addition, Sienna Mapelli Mozzi, the seven-month-old daughter of Princess Beatrice and her husband Edoardo Mapelli Mozzi, and her cousin August Brooksbank - whose parents are Princess Eugenie and her husband Jack Brooksbank - will also ride in the carriage.
The children were recently photographed in the grounds of Windsor Castle practicing getting in and out of the carriage.
It has not been confirmed whether the Cambridge children's cousins, Archie and Lilibet Mountbatten-Windsor - the offspring of Prince Harry and his wife Meghan, Duchess of Sussex - will be involved.
The Sussex family are based in the US but are planning to return for the main Jubilee weekend celebrations, which will mark 11-month-old Lilibet's first trip to the UK and her three-year-old brother's first visit since they relocated after stepping down as senior royals in 2020.
Meanwhile, the queen's granddaughter, Lady Louise Mountbatten-Windsor, will have an important role in the show.
The 18 year old - who is the daughter of Prince Edward and his wife Sophie, Countess of Wessex - will drive the carriage once owned by the Duke of Edinburgh in tribute to her late grandfather and their shared passion for the pursuit.
Meghan and Harry confirmed last week they will be part of the Platinum Jubilee celebrations in a statement released shortly after it was revealed they, along with disgraced Prince Andrew, will not be on the balcony for the traditional Trooping the Colour event as it will be limited to members of the family "currently undertaking official public duties".
A spokesperson for the royal couple said: "Prince Harry and Meghan, The Duke and Duchess of Sussex, are excited and honoured to attend The Queen's Platinum Jubilee celebrations this June with their children."