Don't miss: Prince William's cheeky sons steal the show at King Charles' birthday
UK's pomp and pageantry were on display during the military spectacle.
Prince George and Prince Louis stole the show as they saluted the crowd during the RAF flypast on the Buckingham Palace balcony with their great-grandfather King Charles III as the monarch and his wife Camilla waved to the crowds after performing in the Trooping the Colour parade.
King Charles became the first monarch in more than 30 years to take part in Trooping the Colour on horseback. He took the royal salute as Colonel in Chief of the Household Division's seven regiments during the ceremony and staged on Horse Guards Parade. Members of the royal family and 8,000 spectators watched the whole ceremony.
Watch: King Charles III's horseback ride on birthday. He was joined by…
It was the first time a reigning monarch has ridden at Trooping the Colour since Queen Elizabeth's horse carried her during the 1986 ceremony. UK's pomp and pageantry were on display during the military spectacle in the event for which Charles had deputised for Queen Elizabeth II last year.
The monarch was joined on horseback by the royal colonels - the Prince of Wales Prince William, Colonel, Welsh Guards, the Princess Royal, Gold Stick in Waiting and Colonel of The Blues and Royals and the Duke of Edinburgh.
Travelling in a carriage were Camilla, Kate Middleton and Prince George, Princess Charlotte and Prince Louis.