Cheeky Prince Louis was seen trying to cover his mum's mouth and blowing raspberries in an exuberant display during the Sunday pageant.
Kate Middleton, 40, was seen keeping a close eye on her youngest son - who could be seen pulling a series of expressions.
The prince was spotted upturning his own nose with his thumb and wandering over to sit on Prince Charles's lap during the show after growing restless.
He previously had a cheeky encounter with Mike Tindall who could be seen jokily warning the four-year-old to behave.
The young Prince, four, was also spotted enthusiastically dancing, before pausing to eat a chocolate biscuit.
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He joined his siblings, Princess Charlotte and Prince Louis and parents, the Duke and Duchess of Cambridge, in the royal box to watch the pageant.
He also stole the show during Trooping The Colour after he was wowed by the Red Arrows.
He was photographed chatting to his great-grandmother The Queen as they watched on from the balcony of Buckingham Palace.
On social media, one royal fan wrote: "Oh my Gosh!!!! I can't!! Cuteness overload!! Prince Louis is so freaking adorable!"
Another wrote: "Prince Louis is stealing the show once again."
A third added: "This child is a joy to watch (probably a handful to parent!) but what a super little character he appears to be!"
The four-day spectacle to mark the Queen's incredible 70-year reign finishes today with the Platinum Jubilee Pageant.
Royal revellers lined the Mall to watch the incredible display, that followed a similar route to the Queen's coronation in 1953.
Other royals in the Jubilee Pageant’s box are the Prince of Wales and the Duchess of Cornwall and the Duke and Duchess of Cambridge.
The Princess Royal and Vice Admiral Sir Tim Laurence are also there with Princess Beatrice and her husband Edoardo Mapelli Mozzi, and Princess Eugenie and her husband Jack Brooksbank.
Anne’s son Peter Phillips is joined by his children Savannah and Isla, while Zara and Mike Tindall and the Duke and Duchess of Gloucester have also made an appearance.
Princess Eugenie could be seen bouncing son August on her knee - in his first public appearance.
The one-year-old is wearing a jumper with a Union flag on the front.
