The Queen, 93, broke with her tradition of wearing blue - her favourite colour - in favour of a timeless grey coat embellished with lemon floral embroidery.
The monarch donned a matching hat and accessorised with an exquisite floral brooch speckled with canary yellow diamonds which was a gift from the Sultan of Oman, Daily Mail reports.
Rarely seen without them, the Queen also wore her signature pearl stud earrings and three-tier pearl necklace.
The Queen was on hand to present the iconic Ascot Gold Cup which was won by world renowned jockey Frankie Dettori.
Her Majesty couldn't contain her laughter as she shook hands with the racing pro, who won the first four races on Ladies Day.
The Queen has attended Royal Ascot every year since ascending the throne in 1952.
Queen Elizabeth's granddaughter Princess Eugenie -the youngest daughter of Prince Andrew and Sarah Ferguson - was also at the races, delighting royal fashion watchers in a stunning emerald ensemble from London label Cefinn.
Prince Edward's wife Sophie, Countess of Wessex, was spotted in a navy monochrome outfit featuring an on-trend jumpsuit and matching mesh headpiece.
The Earl of Wessex, who was not photographed on Day Three, celebrated his 20th wedding anniversary to Sophie at Royal Ascot earlier this week.