What did Kate Middleton tell her sneezing son George?

The royal family rounded off King Charles inaugural birthday parade Saturday with a balcony appearance at Buckingham Palace to watch a spectacular fly-past.

In the pictures and videos from the event, George was spotted raising his hands to his mouth as he sneezed.

Prince George's sneeze was caught on camera as the son of Prince William and Kate Middleton accompanied his siblings, mother and Queen Camilla to the Birthday Parade of King Charles.

Sitting across the carriage from him, his mother Kate could be seen sweetly telling him: "Bless you."

Three of the king´s young grandchildren -- future king Prince George, nine, Prince Louis, five, and Princess Charlotte, eight -- joined the rest of the family on the balcony with the princes sporting red ties and blue blazers and Charlotte in a sailor suit with red trim.

They were cheered by the crowds who gathered outside the palace and in The Mall, the avenue leading up to it.

The air display of some 70 military aircraft, following a 41-gun salute from nearby Green Park in central London, came after bad weather cut short a planned fly-past at Charles´s coronation on May 6.

It ended with the Red Arrows, the Royal Air Force´s aerobatic display team, trailing red, white and blue vapours.

Earlier, Charles saddled up for the annual Trooping the Colour parade that marks the British sovereign´s official birthday.

It was the first time the monarch has ridden at the ceremony since his mother, Queen Elizabeth II, in 1986.

Charles, who also took the royal salute, was followed on horseback as he inspected the troops by his eldest son and heir, Prince William, Charles´ brother Edward, the Duke of Edinburgh, and sister Anne, the Princess Royal.

Queen Camilla in a military-inspired red outfit, and William´s wife Catherine, the Princess of Wales, who was dressed in green, followed in a carriage.

The colourful display of regimental precision and pageantry was the first of 74-year-old Charles´s reign.

Charles´s actual birthday is on November 14 but British sovereigns celebrate twice -- once in private and again in public.