Kate Middleton wore Princess Diana's diamond and pearl earrings. Photo / Getty Images
The Duchess channelled her late mother-in-law and wore an elegant high-neck, polka dot dress with a black and white floral hat, paired with Princess Diana's diamond and pearl earrings.
Prince William and Kate Middleton hid away from the heat in the Royal Enclosure. Photo / Getty Images
It is an outfit similar to the one Diana wore 34 years ago when she attended Royal Ascot in 1988. At the time the "People's Princess" opted for a pearl necklace with matching black and white heels and a polka dot hat.
Meanwhile, the Duke wore a dashing suit complete with a light-blue patterned tie and a top hat.
Diana, Princess of Wales at Royal Ascot in 1988. Photo / Getty Images
The couple joined the future King and Queen consort at the event as well as Peter Phillips and his girlfriend Lindsay Wallace, Lady Gabriella Windsor and Prince Michael of Kent.
The Royal Ascot appearances come amid reports the Prince and Princess Michael of Kent are planning to retire from public royal life. The Daily Telegraph has reported the retirement will coincide with the prince's 80th birthday early next month.
Kate Middleton's outfit was very similar to one Princess Diana wore in 1988. Photo / Getty Images
Queen Elizabeth was absent from the event as she continues to battle recent health and mobility issues, but the Daily Mail reported she likely watched from home as two of her own horses are racing in the event.
The Queen, who is a passionate horse breeder and has had 22 of her horses win races at Royal Ascot, was a regular at the meeting since taking the throne in 1952 - only ever missing the event because of pandemic restrictions.
Due to intense temperatures, the usually strict dress code will not be enforced in all enclosures at the popular event and male attendees will be allowed to remove their jackets and ties should they wish.
Prince Michael of Kent and Princess Michael of Kent attend Royal Ascot. Photo / Getty Images
The family occupied the Royal Enclosure, which is invite-only and has a very strict dress code, according to Town and Country.
"Dresses and tops should have straps of one inch or greater," according to the code. "Strapless, off-the-shoulder, halter neck and spaghetti straps are not permitted. Jackets and pashminas may be worn."
Peter Phillips and Lindsay Wallace attend day four of Royal Ascot. Photo / Getty Images
Men are only allowed to remove their hats "within a restaurant, a private box, a private club or a facility's terrace, balcony or garden" or enclosed seating area on the premises.
Everyone in the Royal Enclosure must wear a name tag.
Prince Charles and Camilla attended the event earlier in the week and led the royal family in the carriage procession with Princess Anne, Peter Philips, Zara Tindall and many other royals including Sophie, Countess of Wessex and Princess Beatrice in attendance.
The Duchess of Cambridge's parents Carole and Michael Middleton were also seen at the event.
