Riley, who runs a London Nail and Beauty salon, has been trusted with maintaining and shaping the duchess' eyebrows 2016, when she first visited the boutique on personal recommendation by another member of the royal family.
Sherrille Riley, Meghan's personal brow stylist, told PEOPLE: 'It’s particularly flattering on Meghan because it’s a really natural style and it really compliments her features — she’s a beautiful woman.'
Riley is also known to do Princess Beatrice's eyebrows.
The Royal Ascot was a special occasion for newlyweds Prince Harry and Meghan Markle, who joined other members of the royal family.
The Duke and Duchess of Sussex were given the prestigious task of presenting jockey Frankie Dettori with his winning trophy following the St James' Palace Stakes race on Tuesday afternoon.
Harry and Meghan arrived at the prestigious sporting event, a known favourite by Her Majesty, in a horse-drawn carriage, accompanied by Prince Edward and Sophie, Countess of Wessex.
Meghan opted for a white shirt dress by Givenchy and accessorised with simple black and white accessories.
Harry and Meghan's attendance at Ascot marks a huge break away from tradition for the royals. William and Kate, the Duke and Duchess of Cambridge, did not attend the event together until 2016 – five years after they married.
It is believed they were invited every year, but politely declined until Catherine attended to celebrate the Queen’s 90th birthday in 2016.