During French President Macron's visit to Windsor Castle, the Princess of Wales viewed a reminder of her youngest son

NEED TO KNOW

• Kate Middleton said something alluding to Prince Louis at the state visit from France

• The Princess of Wales shares Prince George, 11, Princess Charlotte, 10, and Prince Louis, 7, with Prince William

• The royal siblings are currently out of school for the summer, and William and Kate's commitments at the state visit didn't take them far from home

Kate Middleton may have dropped an affectionate reference to Prince Louis with a subtle quip during the state visit from France.

The U.K. visit from French President Emmanuel Macron and his wife, Brigitte, began on July 8, where Princess Kate referred to her youngest son while touring an exhibit of items relating to France from the Royal Collection at Windsor Castle.

While viewing the display in the Green Drawing Room, the Princess of Wales, 43, cracked a joke about a portrait of young King Louis XIV, who ruled France from 1643 until 1715.

"I should know," Princess Kate said, according to Hello! magazine.

The Princess of Wales is also knowledgeable when it comes to art history and majored in the subject at the University of St. Andrews, where she met her future husband, Prince William.

The couple wed in 2011 and share children Prince George, 11, Princess Charlotte, 10, and Prince Louis, 7, and Kate and Louis seem to share a special bond. It's also thought that the mother and son share a striking resemblance, something that Kate herself has acknowledged.

"Everyone always comments on how Louis is the spitting image of Kate," a friend previously told PEOPLE. "She loves it and thinks it’s very sweet; she often jokes that he’s the only one of her kids who actually looks like her!"

Prince Louis most recently stepped into the spotlight at Trooping the Colour on June 14, joining his parents and siblings for the annual London parade celebrating King Charles' official birthday. The little prince's personality shone during the pageantry there, from flashing a genuine grin (showing off his missing front teeth) in the carriage procession and making sure to get the last wave when the royals departed the Buckingham Palace balcony.

Louis and siblings are officially out from school for the summer, and their parents didn't have to travel far from home for their involvement in the state visit from France. The official trip was hosted from Windsor Castle, where they live nearby, instead of the more traditional Buckingham Palace as the London royal residence undergoes extensive renovations.

The departure marked the first time a state visit was hosted at Windsor in 11 years, and royal watchers were charmed by a portrait that the Prince and Princess of Wales released before the state banquet capping the first day of the Macrons' stay.

"Ready for what promises to be a wonderful State Banquet this evening in Windsor," William and Kate's team wrote below the portrait of them released on the evening of July 8.

The shot showed the royal couple all dressed up in their white-tie finery, including a triumphant tiara return for Princess Kate, standing outside in a picturesque setting.

The Prince and Princess of Wales could have gotten glam at their Adelaide Cottage home and posed for the photo before heading out, or they may have taken the picture elsewhere within the vast grounds of Windsor.