Kate, who shares three young children with William, has made a gradual return to public engagements this year since announcing in January that she is in remission from cancer. Kate has not shared details of the type of cancer with which she was diagnosed, though she has shared she underwent chemotherapy treatment.

As for which member of the Royal Family is an expert at picking winners, Harrold noted, "Queen Camilla is very much into horses. The King is, but I would say Camilla is more so, along with Princess Anne. If you're going to be taking advice on which horses, I would look at Camilla for a good tip."

Kate Middleton has pulled out of a scheduled return to Royal Ascot. The Princess of Wales was set to return to the annual horse racing event with Prince William for the second day of racing on Wednesday, June 18.