Trooping the Colour: Why the King has 2 birthdays? Prince William, Kate & kids gather for celebrations | See Pictures

Britain is celebrating the official birthday of King Charles III today, June 13, with Trooping the Colour, a massive display of royal pageantry featuring 1,500 soldiers, 200 horses, and thousands of spectators.

Though King Charles was born on 14 November 1948, the British sovereign’s official ceremony is always held in June. This historic tradition originated in 1748 during the reign of King George II.

Because his November birth month was deemed too cold for a grand outdoor parade, George II chose to align his birthday celebrations with the annual summer military parade, a practice that remains a cornerstone of the royal calendar today.

As noted by the British military’s Household Division, these flags served a crucial safety purpose before the advent of modern communications, acting as a visible rallying point to keep troops from becoming disoriented or separated during active conflict.

The phrase “trooping the colour” itself stems from a classic military training exercise. Young officers would march, or "troop," through the rows of soldiers while holding the flags high, ensuring every member of the regiment could easily identify their unit's specific colours on the battlefield.

For the first time in 90 years, the King's Company, 1st Battalion Grenadier Guards, is at the centre of the ceremony, and will be in their colour in front of a king, according to Britain's Ministry of Defence.

Over the years, the 1st Battalion Grenadier Guards frequently “trooped their colour” for the Queen's birthday parades, but have not trooped for a king since June 1936.

Their last king's birthday parade was for King Edward VIII, the only such parade of his short reign.

Once on-site, the ceremony unfolds with a formal royal salute and a meticulous troop inspection by the King.

Audiences will then witness the Massed Bands of the Foot Guards perform a musical "troop" as the regiment’s historic "colour" is escorted through the ranks, culminating in a grand march past the monarch.

The King then travels back to Buckingham Palace.

For many watchers, this is the most highly anticipated moment of the day. The airshow, which sees jets pump trails of red, white and blue into the sky.

Younger royals, including Prince William and Princess Kate's three children: Prince George, 12; Princess Charlotte, 11 and Prince Louis, 8, were present at the Buckingham Palace balcony.

The event typically draws massive crowds to The Mall, London’s premier ceremonial route connecting Buckingham Palace to Trafalgar Square. Thousands of UK residents, international tourists, and global media representatives line the avenue to witness the parade’s traditional conclusion—a spectacular military flypast over the palace.