The two eldest children of the Prince and Princess of Wales formed part of a procession with the royal family, following the coffin as it entered London’s Westminster Abbey. Their attendance was confirmed by Buckingham Palace Sunday night with the release of the order of service for the event. The program listed the two Cambridge children, who are second and third in line to the British throne, among the royal procession behind the Queen’s coffin. George, aged 9, and Charlotte, 7, along with their parents, Prince William and Catherine, Princess of Wales, are joining world leaders, politicians, public figures and European royals, as well as more than 500 dignitaries from around the world, in mourning Britain’s longest-reigning monarch, who died on September 8 at the age of 96. The siblings followed the coffin behind their parents and ahead of their uncle and aunt, the Duke and Duchess of Sussex. Read MorePrince Louis, their 4-year-old younger brother, is not attending the funeral. The service, which is expected to be attended by more than 2,000 guests, will include Bible readings and traditional hymns, as well as a sermon from the Archbishop of Canterbury, Justin Welby.