King Charles and Queen Camilla are back in their carriages for Royal Ascot — and hoping for a winner. The King’s horse Purple Rainbow, bred by the late Queen Elizabeth, is set to race on the fourth day of Royal Ascot on June 20. On another day of intense heat, the King, 76, who is undergoing treatment for an undisclosed cancer, led the royal family’s appearance at the annual race festival. He arrived with Queen Camilla in the first carriage of the royal carriage procession that started shortly after 2 p.m. local time. While the Queen, 77, went with a summer white ensemble and matching hat, the King looked dapper in a grey suit with a pink vest underneath, plus a top hat. Although they didn't ride in the carriage procession, there were other royal family members in attendance on Friday. Mother and daughter pair Sarah Ferguson and Princess Eugenie were spotted chatting with the monarch and his wife, as was Zara Tindall, who won a silver medal in equestrian events at the 2012 Olympics. When the races began on June 20, the royal couple had more than a spectator’s keen interest in the races, with Purple Rainbow set to run in the Sandringham Stakes. Taking the reins will be 17-year-old jockey Warren Fentiman, who recently told The Telegraph: "It’s just mind-blowing that I’m riding for the King." As he watches through his binoculars, King Charles will be hoping that Purple Rainbow does better than his horse Reaching High, which didn’t quite live up to that name, finishing ninth on the first day of Royal Ascot earlier in the week. There appeared to be more luck in the wider royal party on June 19. Then, Charles’ niece Princess Beatrice looked like she may have had a winner when she joined the other members of her family in the royal box. She was pictured excitedly cheering on a horse in one of the races. The King is expected to attend all five of the race days, which end on June 21. The royals have been out in force all week at Royal Ascot, with one notable exception: Kate Middleton. The Princess of Wales, 43, pulled out at the last minute, and Prince William appeared solo at the races on June 18. She is continuing to manage her appearances at public events amid her recovery from cancer treatment. Princess Kate announced in January that she was in remission from an undisclosed type of cancer. In contrast with the previous day, there were no members of the royal family in the arrival procession across the course and into the main grandstand and parade ring on June 20. Among those accompanying Charles and Camilla were musical writer Andrew Lloyd Webber, referred to using his formal title Lord Lloyd Webber, and his wife Madeleine in the fourth carriage. With them was the most senior courtier in the royal household, the Lord Chamberlain Richard Benyon (the Lord Benyon). Appointed in November 2024, he has another royal link: he is close to the family of Princess Kate, and it was on his estate that Pippa Middleton married James Matthews in 2017. Can't get enough of PEOPLE's Royals coverage? Sign up for our free Royals newsletter to get the latest updates on Kate Middleton, Meghan Markle and more! On June 20, actor Nigel Havers, who starred in the 1980s movie Chariots of Fire, was set to present the trophy for the Commonwealth Cup, while former tennis star Annabel Croft is scheduled to hand out the trophy for the Duke of Edinburgh Stakes.