Charles and Camilla joined other royals to mark the King's official birthday over the weekend, where eagle-eyed observers may have noticed a colourful accessory on Charles' wrist

King Charles and Queen Camilla, who were greeted by applause from the large crowds, were joined by Prince William and Princess Catherine to mark the monarch’s official birthday.

Thousands of people have lined the streets to see the royals for the annual Trooping the Colour.