The Prince and Princess of Wales enjoyed the first day of the French state visit on Tuesday, along with the King and Queen.
Though William and Kate's three children were not in attendance, the princess seemingly took the opportunity to make a subtle reference to her youngest child while viewing an exhibition of art from the Royal Collection at Windsor Castle.
While looking at a number of artefacts, Kate jokingly remarked about a portrait of young King Louis XIV: "I should know."
The royal studied history of art at the University of St Andrews and so has a keen eye for portraiture. The current course offers students the opportunity to assess art from the medieval period to the present day.
Kate and Louis' joint outings
Though Louis himself wasn't present during day one of the state visit, he did join members of the royal family at Trooping the Colour 2025.
The seven-year-old royal joined his mother, as well as his brother Prince George and sister Princess Charlotte, in a carriage ride down the Mall before standing on the Buckingham Palace balcony to wave at well-wishers.
Putting his cheeky nature on full display, Louis grinned at the crowds, realising that waving enthusiastically earned him a chorus of cheers from the public.
He also joined his parents to watch a military procession down The Mall to mark the 80th anniversary of VE Day in May.
Again, he showed his playful side by jokingly emulating his brother, who had pushed his hair out of his face with a dramatic sweep of his hand.
A low-key royal outing
Though heading out on royal engagements isn't an everyday occurrence for young Louis, he did have the opportunity to try his hand at a spot of archery while taking part in the Big Help Out during a visit to the 3rd Upton Scouts Hut in Slough in 2023.
Louis also lapped up the chance to drive a digger alongside his father before tucking into marshmallows melted over a campfire.
It was during this outing that Kate revealed her sweet nickname for her youngest son. "Pop that in the fire, Loubugs," the princess said, instructing him to dispose of the stick his marshmallow was toasting on.