Greeted by huge cheers, it was the first time the Prince has arrived to the annual event with his grandmother, and the pair waved to the royal watchers as the Royal Procession made its way through the Berkshire racecourse.
CLICK ON PHOTO FOR GALLERY
Prince Harry sits opposite Queen Elizabeth II during the Royal Procession
Also joining the Prince and the Queen in the carriage were the Duke of Edinburgh, Prince Philip, and the Duke of York, Prince Andrew. The procession also included Prince Charles, the Duchess of Cornwall, and Princesses Beatrice and Eugenie.
Underneath the coat she donned a blue floral print dress.
The Prince wore a pale yellow waistcoat under his tails, and a tie which matched his grandmother's outfit, while Princess Beatrice looked summery in a teal green dress with a lace overlay by British designer Suzannah.
Prince Harry at Royal Ascot
A wide cuff on her wrist kept the accessories on trend, while the wide hat was created by milliner Sarah Cant.
Princess Eugenie meanwhile looked pretty in pale pink, with her hair tied back in a low chignon and covered with a hat by milliner Nerida Fraiman.
The Queen is a keen supporter of Royal Ascot and is constantly kept informed of the order and the development of the racing programme throughout the year.
She has owned 22 winning horses including Estimate, last year's winner of the historic Gold Cup. This year will see Estimate compete once again for the Gold Cup.
Princesses Beatrice and Eugenie at Royal Ascot
For more than 300 years, Royal Ascot has become an integral part of the British social calendar. Immersed with tradition and pageantry, the event is attended by thousands of race-goers who are all dressed to impress.
The five-day meeting commences with the Royal Procession, and the arrival of the Queen and the royal party in horse-drawn landau carriages is televised each year.