Catherine, Princess of Wales, joined other British royals on the balcony of Buckingham Palace for the King’s official birthday, marking her first public appearance since being diagnosed with cancer. The Princess of Wales, her husband William, and their children George, Charlotte, and Louis gathered with King Charles and Queen Camilla to watch a Royal Air Force flypast. They waved and smiled at the crowd, who responded with cheers.

The Princess, also known as Kate, was earlier driven in a state carriage with her children from Buckingham Palace to Horse Guards Parade to watch the celebration, known as Trooping the Colour. She wore an Irish Guards regimental brooch, acknowledging her role as their honorary colonel. The family was later seen watching events from a viewing point while Kate’s husband, William, the Prince of Wales, rode on horseback.

This was Kate’s first public appearance since Christmas Day, weeks before her cancer diagnosis. She stepped away from public duties in January, following surgery for a non-cancerous abdominal condition. In March, amid speculation about her well-being, she revealed she had been diagnosed with cancer after the operation and was undergoing treatment.

King Charles III and Queen Camilla were also taken in a carriage from Buckingham Palace, bringing cheers from the packed crowds as they made their way slowly up The Mall. The King rode in a carriage rather than on horseback this year due to his cancer diagnosis. People of all ages gathered along the length of The Mall for the event, with some onlookers wearing Union Jack bucket hats and fascinators, waving flags, and singing the national anthem.

Kate gave an update on her health on Friday, saying she had made “good progress” in her recovery. However, she noted that she expected her treatment to last a few more months and was “not out of the woods yet.”

Trooping the Colour is a magnificent military spectacle featuring 1,400 officers and soldiers, 400 musicians, and 200 horses processing through the streets of London from Buckingham Palace to Horse Guards Parade, while crowds line the route. The event, one of the highlights of the royal calendar, has marked the official birthday of the British sovereign for more than 260 years, though Charles’s actual birthday is in November.

Since the 18th century, Britain’s kings and queens have held both a public celebration – the official birthday – and a more private event on their actual birthday.

The tradition of celebrating the British sovereign’s official birthday, separate from their actual birthday, is believed to have originated with King George II in 1748. Like King Charles III, who was also born in November, George II’s decision was likely influenced by the unpredictable and often unfavourable weather in Britain during that month.

As events at Trooping the Colour approached their conclusion this year, the weather took a turn for the worse. Crowds awaiting King Charles’s return to Buckingham Palace were subjected to heavy rain and gusty winds, causing some onlookers to struggle with their umbrellas.

Speaking about Kate’s appearance on the balcony, David Betteridge, 66, expressed optimism about her health, noting that “she looked well so hopefully that is a good sign.” He added, “It’s nice to see her back actually.”

Anna Yang, 30, visiting from China, shared her excitement about witnessing the flypast from her nearby hotel, describing it as a spectacular sight of national aircraft in the sky.

Despite the celebratory atmosphere, there were also anti-royalist demonstrators present, chanting slogans such as “shame” and “not my king!”

This year’s Trooping the Colour ceremonies were adapted due to King Charles’s ongoing treatment for an unspecified form of cancer. While his doctors have been encouraged by his progress, allowing him to resume public duties in April, each engagement is carefully reviewed and adjusted as necessary.

During Saturday’s events, King Charles reviewed the troops seated alongside Queen Camilla in an Ascot landau carriage. Notably, three horses from the British Army that had bolted in London in April returned to duty and participated in the birthday parade. The remaining two horses are currently enjoying a summer break in the Chilterns and will return to service in due course, according to the army.