Louis complied briefly but soon returned to his attempt at engaging with their father.

The mischievous behaviour of Prince Louis, who has become known for his playful antics during official functions, once again delighted royal watchers.

Princess Charlotte, positioned in front of Kate, Princess of Wales, also attempted to keep Prince Louis in check during this year’s Trooping the Colour.

While watching the parade from the Major General’s Office overlooking Horse Guards Parade, Prince Louis was seen yawning, dancing to the Scots Guards’ march, and chatting with Princess Kate.

According to lip reader Nicola Hickling, Charlotte appeared to admonish Louis.

The expert believes the young royal said: “You have to stop doing that. Watch the parade.”

Despite her efforts, Louis reportedly responded with a defiant: “I won’t.”

Charlotte’s insistence to “do as you’re told” was met with a resolute “nope” from her younger brother, the lip reader said.