Kate Middleton and Prince William Crack a Joke About Prince Louis' Cheekiness at the Platinum Jubilee

Queen Elizabeth was undeniably the star of the Platinum Jubilee, but Prince Louis might have had the most fun!

Kate Middleton and Prince William ended the four days of celebrations on Monday by sharing a social media post — and they couldn't help but acknowledge their 4-year-old child's scene-stealing antics.

"What a fantastic weekend of celebrations. Seeing people across the nation coming together with family, friends and loved ones has been extremely special," they wrote. "Thank you to everyone who turned out to show their gratitude to The Queen and her inspiring 70 years of leadership. From the crowds on the Mall to communities hosting street parties up and down the country, we hope you had a weekend to remember."

Prince William and Kate then quipped, "We all had an incredible time, especially Louis…" with the eyes emoji.

The Duke and Duchess of Cambridge signed the note with their initials — indicating its personal nature — and completed the posts with a black and white photo of Prince William and Prince Louis walking together during Trooping the Colour.

Prince Louis attended Trooping the Colour on Thursday, taking part in his carriage ride debut alongside siblings Prince George, 8, and Princess Charlotte, 7. Sitting between his older brother and sister, he enthusiastically waved to the crowds — even when Charlotte tried to stop him.

For more on the Queen's Platinum Jubilee, listen below to our daily podcast PEOPLE Every Day.

To make things even more adorable, Prince Louis wore the same mini sailor suit that his father wore to Trooping at age 2 in 1985. (The same year Louis' uncle, Prince Harry, made his own Trooping the Colour debut!)

When they arrived to watch the Horse Guards' Parade, Prince Louis joined his siblings and cousins in hanging by the windows to catch the action. He even looked like a pro as he saluted the troops below while standing beside a fellow great-grandchild of the Queen's, 3-year-old Lena Tindall, the daughter of Zara and Mike Tindall.

Then Prince Louis hopped back in the horse-drawn carriage to head to Buckingham Palace, where he joined his family and working royals for the big balcony appearance as they watched a flypast by the Royal Air Force.

The little prince could be seen alternately covering his ears with his hands during the noisy flypast, waving to the crowd and chatting with the Queen, who appeared amused by his antics.

Meanwhile, Kate repeatedly reminded her youngest child to take his hands out of his mouth, at one point saying, "Good boy."

On Saturday, Prince Louis stayed home while Prince George and Princess Charlotte accompanied their parents to a visit in Wales. The two eldest Cambridge kids also attended Saturday night's Platinum Party at the Palace, excitedly waving U.K. flags and enjoying performances by Queen + Adam Lambert, Diana Ross and more.

Prince Louis had a front row seat to the festivities again on Sunday, when the Cambridge family gathered for the weekend's big finale: the Platinum Jubilee Pageant.

Prince Louis pointed out elements of the parade to Kate, "read" the program and stood up on his seat to get a better look.

Although he made a few cheeky faces at his mom, he also cuddled sweetly with Kate — and took turns also sitting on the laps of dad Prince William and grandfather Prince Charles!

Can't get enough of PEOPLE's Royals coverage? Sign up for our free Royals newsletter to get the latest updates on Kate Middleton, Meghan Markle and more!

To cap off the weekend, Prince Louis joined his family on the Buckingham Palace balcony again for Queen Elizabeth's surprise appearance.