Prince William and Princess Kate's Garden Party Guests Give Major Clue as to Who Will Be Their "Rock" When He Becomes King

Prince William and Princess Kate attended the final Buckingham Palace garden party of the year on Tuesday, May 20, and the royal couple invited some close family members to join them at the elegant event. While the couple have been taking steps to prepare Prince George for his eventual role as King, they've also been prepping themselves for their future on the throne—and their guests at Tuesday's garden party give some hints about who William and Kate will rely on one day.

The Prince and Princess of Wales were joined by William's uncle, Prince Edward, and his wife, Duchess Sophie, William's cousins Princess Eugenie and Zara Tindall, and Queen Elizabeth's first cousin, the Duke of Gloucester, and his wife, the Duchess of Gloucester.

Kate's "royal sister" Duchess Sophie is said to have been a great source of comfort while the Princess of Wales battled cancer last year, and Princess Charlotte has joined Sophie for girly shopping trips in London. It's also been reported that the Prince of Wales is considering making Edward and Sophie's 21-year-old daughter, Lady Louise, a working royal one day.

The Wales family is also close with Zara and her husband, Mike Tindall—and body language expert Darren Stanton recently shared that the Olympic equestrian has become a "rock" for the Royal Family.

"She clearly thinks highly of her family and has developed strong bonds with everyone," Stanton said, speaking on behalf of Betfair Slots. "They seem to see her as a real rock who can always be relied on. Family is very close to her heart."

King Charles has been said to want Princess Eugenie and Princess Beatrice to stay in the royal fold, even if they likely won't become full-time working members of the family.

"While King Charles remains keen to keep Beatrice and Eugenie close, deploying them at garden parties and receptions, neither will receive the full-time royal roles that their father [Prince Andrew] once coveted for them," Daily Mail columnist Ephraim Hardcastle wrote in January.

As for garden party fashion, the Princess of Wales—who wore an olive Victoria Beckham suit to present the Queen Elizabeth II Award for British Design last week—repeated the pale yellow dress she wore during the Platinum Jubilee, adding a slightly different floral-trimmed hat.

She gave a sentimental touch to the look with her diamond wedding earrings, which feature a dangling acorn, as featured on the princess's coat of arms. Meanwhile, Duchess Sophie wore a pretty pink floral dress, while Zara dressed in a long-sleeved white floral midi dress and Eugenie looked lovely in navy polka dots.