Princess Catherine joins royals for first public apparancee since cancer diagnosis

Britain's Prince George (from left), William Prince of Wales, Prince Louis, Princess Charlotte and Catherine Princess of Wales watch a flypast on the balcony of Buckingham Palace following the annual Trooping the Colour parade in London, Britain, on Saturday. Photo by Tolga Akman/EPA-EFE
Britain's Prince George (from left), William Prince of Wales, Prince Louis, Princess Charlotte and Catherine Princess of Wales watch a flypast on the balcony of Buckingham Palace following the annual Trooping the Colour parade in London, Britain, on Saturday. Photo by Tolga Akman/EPA-EFE

June 15 (UPI) -- Princess Catherine participated with other royals for the celebration of King Charles III' official birthday Saturday in her first public appearance since being diagnosed with cancer earlier this year.

The 42-year-old Princess of Wales, her husband Prince William, and their three children, George, Charlotte and Louis, appeared on the balcony with the king and Queen Camilla to watch a Royal Air Force flyover.

They were cheered by the spectators on a drizzling Saturday morning in London.

The Royal Family posted video of the event.

The princess earlier was driven in a state carriage with her children from Buckingham Palace to Horse Glades Parade for the Trooping the Colour.

Prince George (from left),William Prince, Prince Louis, Princess Charlotte, Princess Catherine, King Charles III, Queen Camilla, Duchess Sophie, Duke Edward Duke, Lady Louise, Princess Anne stand on the balcony of Buckingham Palace at the annual Trooping the Colour on The Mall in London on Saturday. Photo by Hugo Philpott/UPI
Prince George (from left),William Prince, Prince Louis, Princess Charlotte, Princess Catherine, King Charles III, Queen Camilla, Duchess Sophie, Duke Edward Duke, Lady Louise, Princess Anne stand on the balcony of Buckingham Palace at the annual Trooping the Colour on The Mall in London on Saturday. Photo by Hugo Philpott/UPI

Then they watched the events as her husband William, the Prince of Wales, rode on horseback.

In Trooping the Colour, 1,400 officers and soldiers, together with 400 musicians and 200 horses, go through the streets of London from Buckingham Palace to Horse Guard's Parade. Crowds lined the route.

Princess Catherine and her daughter Princess Charlotte travel in a Royal carriage at the annual Trooping the Colour on The Mall in London on Saturday. Photo by Hugo Philpott/UPI
Princess Catherine and her daughter Princess Charlotte travel in a Royal carriage at the annual Trooping the Colour on The Mall in London on Saturday. Photo by Hugo Philpott/UPI

The event marks the official birthday of the British sovereign for more than 260 years. Charles' actual birthday is Nov. 14, when he turned 75.

Kate has last appeared in public on Christmas Day, which was weeks before she revealed her cancer diagnosis.

King Charles III and Queen Camilla travel in a Royal carriage at the annual "Trooping the Colour" on The Mall in London on Saturday, June 15, 2024. The ceremony happens annually and dates back to the era of King Charles II. Photo by Hugo Philpott/UPI
King Charles III and Queen Camilla travel in a Royal carriage at the annual "Trooping the Colour" on The Mall in London on Saturday, June 15, 2024. The ceremony happens annually and dates back to the era of King Charles II. Photo by Hugo Philpott/UPI

On Friday, Kate gave an update on her health, saying she had made "good progress" in her recovery, including chemotherapy. She said she was "not out of the woods yet" with several more months of treatment.

King Charles III takes a salute in front of his armed forces at the annual Trooping the Colour on The Mall in London on Saturday. Photo by Hugo Philpott/UPI
King Charles III takes a salute in front of his armed forces at the annual Trooping the Colour on The Mall in London on Saturday. Photo by Hugo Philpott/UPI

"I have been blown away by all the kind messages of support and encouragement over the last couple of months," she wrote. "It really has made the world of difference to William and me and has helped us both through some of the harder times."

Charles also has been undergoing cancer treatment since a diagnosis in February. He was allowed to resume public-facing duties in April.

"Most of us are surprised that she is here today," Katie Nicholl, an NBC News royal contributor, said. "We know that as the King and the Princess of Wales have gone through this cancer journey together, they've very much been supporting each other behind the scenes. Well this is the ultimate show of support."