Kate Middleton, Prince William versus Princess Diana, Prince Charles' kiss

Royal Charity Polo Day held at the Guards Polo Club is where the Duke and Duchess of Cambridge, both 41, delighted onlookers with a rare public display of affection. 

Just before Prince William was awarded his trophy, the couple shared a sweet kiss on both cheeks, evoking memories of his parents' amorous moments on the polo field. 

Princess Diana would often support Prince Charles at his polo matches during their marriage, and their public displays of affection included lip-to-lip kisses.

While the sight of Prince William and Princess Kate engaging in such public affection may be a surprise to some, royal etiquette expert Myka Meier clarified that there are no strict protocols governing the level of romance displayed by royal couples in public. It is entirely up to their personal discretion.

The echoes of the past were undeniable as Prince William and Kate's tender moment harkened back to the loving embraces and kisses shared by Prince Charles and Princess Diana during their polo match outings. 

These gestures of affection on the field serve as a touching reminder of the enduring legacy of love within the royal family.

"Senior members of the royal family would likely not be told how to interact or when they can or can not show PDA and would be trusted to use their better judgment as to when it's appropriate," the director of Beaumont Etiquette said.