Meghan Markle and Prince Harry returned to the Audi Polo Challenge on what would have been Princess Diana's 57th birthday

Meghan Markle and Prince Harry returned to the Audi Polo Challenge on what would have been Princess Diana’s 57th birthday.

The Duke and Duchess of Sussex arrived at the annual charity event on Sunday together.

Meghan, 36, opted for a casual white button-down shirt and a pair of form-fitting black capri pants, which she accessorized with a pair of black flats, sunglasses and what appears to be the same Madewell x Biltmore Panama hat that she wore to the event on Saturday.

Meanwhile, Harry was seen arriving in a white polo shirt with stripes on the side, which he paired with white pants and boots.

Credit: Stephen Lock/i-Images

Meghan also attended the event on Saturday, as she cheered on Harry and his brother Prince William while the royal brothers took to the field at the Coworth Park Polo Club. William was not seen arriving at the event on Sunday.

The Audi Polo Challenge likely holds a special place in Meghan and Harry’s hearts: Their appearance at the game last year was the first time the couple attended a public event together, and they marked the milestone with a kiss.

Prince Harry
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Also present was actor Eddie Redmayne, who attended Eton College in the early 2000s with William. In addition to playing on the same rugby team, they were also honored as members of the elite group of seniors tasked with exercising discipline at the school.

Prince Harry and Eddie Redmayne
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In a sweet nod to Diana, Meghan and Harry found many ways to honor her legacy during their May wedding.

During the ceremony, Meghan’s wedding bouquet, which featured flowers Harry picked himself from their private garden at Kensington Palace, included Diana’s favorite flowers: Forget-Me-Nots.

The Duke and Duchess also included another one of Diana’s favorite flowers — white garden roses — in a unique floral display in St. George’s Chapel.

RELATED VIDEO: How Prince Harry and Meghan Markle Subtly Honored Princess Diana in Their Wedding Photos

Later on the special day, Meghan was seen wearing Diana’s aquamarine ring on her right hand while she and her husband were seen leaving for their wedding reception.

Diana famously wore the emerald cut Aquamarine stunner to an auction of her own clothes at Christie’s in 1997.

Meghan Markle and Princess Diana
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In one sweet last nod to Harry’s later mother, the couple included a special detail in one of their wedding photos!

In an image released by the palace, while Meghan sits on the floor of the Green Drawing Room at Windsor Castle, Harry sits on an emerald green couch. It was the same couch on which Harry’s late mother was photographed sitting while holding a baby Harry at his christening in 1984.

Prince Harry, Meghan Markle and their pageboys and bridesmaids pose in the Green Drawing Room at Windsor Castle
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Queen Elizabeth II, Princess Diana holding Prince Harry and Prince Charles all pose at their second son’s christening alongside other members of the royal family in 1984
| Credit: Anwar Hussein/Getty

Diana sat next to Queen Elizabeth while Prince Charles rested on the antique furniture’s arm next to her. In the middle of the photo was a young William in a white polo shirt and baby blue shorts as he grinned off-camera.