The racer then stands for a photograph with the Duke and Duchess.
As is traditional, the Royal Family travelled in a series of carriages to the course which is on Crown land and has a long link with the monarchy.
The designer of her wedding dress had been a closely kept secret, with even the most dedicated of fashion followers surprised on the day when the designer, Givenchy, was finally named.
Royal Protocol extends only for official, diplomatic and state events, dictating where to sit and who enters the room first amongst others.
Prince Harry and Markle received rapturous welcome and later presented a winner's trophy to jockey Frankie Dettori, who kissed her hand.
Meghan Markle wore a remarkably loose-fitting dress to a wedding over the weekend, sparking rumors that she's pregnant with her first child with Prince Harry.
Queen Elizabeth II and Princess Anne attend day one of Royal Ascot
Meghan wore a black and white Philip Treacy fascinator, which shaded the top of her face, and carried a black clutch bag.
Hats are a must at Royal Ascot, according to the dress code, although female racegoers have embraced increasingly more outlandish headgear in recent years.
Why? Well like most things royal, it all comes down to history. The late Princess of Wales also wore a white, monochrome outfit when she attended the annual racing event 32 years ago.
Due to health complications, Markle unfortunately had to back out of walking his daughter down the aisle at her royal wedding to Prince Harry on May 19.
Kensington Palace recently announced that Harry and Meghan's first official foreign trip as a couple would be to Dublin in July.
For her visit today, Sophie looked handsome in a mid-length dress in a attractive shade of baby pink.
Each day of the Royal Ascot begins with the Royal Procession, where members of the royal family travel in Ascot Landaus from Windsor Castle to the racecourse.More news: Rudy Giuliani says Trump could pardon Manafort after Russia probe
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