Princess Kate’s subtle but stern balcony exchange with Prince Louis exposed by royal lip reader

As the royal family gathered on the Buckingham Palace balcony for the grand finale of Trooping the Colour, all eyes were on the youngest royal, Prince Louis, and his famously cheeky behaviour.

But this year, during King Charles’ official birthday celebration, the young prince remained composed and well-behaved, thanks in part to a timely reminder from his mother.

While Prince Louis was mostly kept in line by his older siblings, Prince George and Princess Charlotte, Princess Kate reportedly had to give one simple but firm instruction as the national anthem began, according to the Mirror.

Professional lip reader Jeremy Freeman observed that after the Red Arrows’ aerial display, Princess Kate turned to her children and quietly said, “National anthem. Louis, stand.”

Prince Louis quickly straightened up and focused as the anthem began — a moment that showed both the young royal’s growing maturity and his mother’s steady guidance.

Elsewhere on the balcony, King Charles and Prince William were seen exchanging reflections on the day’s events.

Mr Freeman claims that Prince William turned to his father and said, “Oh my word, what a day,” to which the King responded, “Great theatre.”

In another candid exchange, King Charles pointed to one of the aircraft soaring overhead and asked, “What is that?”

Prince William guessed, “Errr, is that Poseidon?” before Prince George confidently confirmed, “It’s a Poseidon, yeah.”

The royal family later shared highlights from the event across their social media platforms.

In a video posted by the Prince and Princess of Wales, Prince William was seen riding on horseback in full military dress, while Prince Kate and the children travelled by carriage down the Mall.

King Charles and Queen Camilla also shared a behind-the-scenes video capturing the family’s procession, the RAF flypast, and a charming moment of the King feeding a carriage horse.

In the caption, the King and Queen expressed their gratitude to the military personnel who helped make the event “truly triumphant.”

This year’s Trooping the Colour marked the third of King Charles’ reign, with the King’s Colour of Number 7 Company Coldstream Guards — the sovereign’s bodyguard — on proud display as the regiment celebrated its 375th anniversary.