The King was joined by his son, Princess Catherine, and his grandchildren, Princess Charlotte, Prince George and Prince Louis on the balcony to watch the spectacle. However, after the flyover wrapped up, the King, 77, and Queen, 78, waved to the crowds below and turned around, appearing to be heading indoors.

It was then that Prince William seemed to exchange a few words with his father, who turned back around to stay with his family, just as the national anthem began.

Everyone stood to attention as the crowd bellowed God Save the King, as per royal protocol. The King and Queen then once again waved to the crowds below and went inside the palace to the Centre Room, with the rest of the family following shortly after.

Courtiers expressed thanks to the personnel involved with the day's celebrations, writing online: "With thanks to the 1,400 members of the Armed Forces who took part in today’s Trooping the Colour, and with special mention to the Grenadier Guards who trooped their new Colour. We salute you."

The June 13 celebration is somewhat of a royal quirk. The King's actual birthday is on November 14, but the royal family has held a celebration on the second Saturday of June for more than 260 years to mark the monarch's 'official' birthday, called Trooping the Colour.

This summer celebrations makes it possible for the royals to hold a large outdoor public event, when it is less likely to be ruined by the great British weather.