It was a Trooping the Colour to remember over the weekend as King Charles marked his official birthday celebration on Saturday—a long-standing tradition where the British monarch publicly acknowledges their birthday in June versus the actual day in order to take advantage of better weather.

Kate Middleton and royal family unite at King Charles III's birthday parade, with the Princess of Wales wearing an ensemble reminiscent of late mother-in-law Princess Diana.

Kate Middleton opted for a bold hue, as her Trooping the Colour ensemble was a vibrant shade that she seemingly pulled from Princess Diana's playbook.