Princess Catherine Whispers Two Words and George, Charlotte and Louis Instantly Snap to Attention on Palace Balcony

Kate Middleton  was in mom mode at  Trooping the Colour . The British royal family gathered in London on June 14 for King Charles' birth...

Kate Middleton was in mom mode at Trooping the Colour.

The British royal family gathered in London on June 14 for King Charles' birthday parade, culminating with an appearance on the Buckingham Palace balcony to watch an aerial flypast. Princess Kate, 43, and Prince William, 42, stood with their children — Prince George, 11, Princess Charlotte, 10, and Prince Louis, 7 — who knew exactly what to do when "God Save the King" played.

Just before the music started, the Princess of Wales appeared to lean down slightly and tell her kids, "National anthem." George, Charlotte and Louis instantly stood up straight with their hands at their sides, standing at attention for the duration of the song.

The royal family at Trooping the Colour on June 14, 2025. Chris Jackson/Getty

In addition to Kate's quick reminder to her children, Prince George made sure to keep Prince Louis from getting too rambunctious on the palace balcony. George, who is second in the line of succession to the throne, was spotted telling his little brother to "stop" waving when he realized no one else was doing so.

Prince Louis at Trooping the Colour on June 14, 2025. Chris Jackson/Getty

Prince George, Princess Charlotte and Prince Louis are now pros at Trooping the Colour, having all attended the annual event since they were babies.

George made his debut at the monarch's public birthday celebration when he was just under two years old in 2015, appearing in his father's arms for the public moment. The following year, Princess Charlotte joined her parents and older brother for the first time.

Prince Louis made his Trooping the Colour balcony debut in 2019, immediately displaying his cheerful personality by "waving" at the crowd and marveling at the airplanes taking flight overhead.

Prince Louis, Prince George, Kate Middleton and Princess Charlotte at Trooping the Colour on June 14, 2025. Jonathan Brady/PA Images via Getty

In 2022, the trio started riding in the carriage procession of Trooping the Colour, taking their royal waves through the streets of London to greet onlookers.