He's a 33-year-old married father-of-two with a responsible job as an air ambulance pilot, not to mention being the future King.
But you're never too old or important for a ticking off from your gran, as hilarious footage of the Queen scolding Prince William on the balcony of Buckingham Palace reveals.
The monarch was seen tapping the Duke of Cambridge on the arm and gesturing him to stand up as he crouched down to tend to a boisterous Prince George.
Close examination of the moment appears to show the monarch saying: "Stand up William."
In any case her meaning was perfectly clear from her hand gestures.
She tapped William on the shoulder and then made an upward motion with her right hand in case he hadn't got the message.
William rose to his feet, looking rather sheepish over the public telling off from his 90-year-old grandmother.
Thousands of people lined the streets of London today to take part in the Queen's birthday celebrations last Saturday.
Princess Charlotte made her official debut on the balcony of Buckingham Palace as the Royal Family observed the RAF flypast
Before the fly past the Queen attended the Trooping the Colour ceremony at Horse Guards Parade, which is playing host to 1,400 soldiers, 200 horses and more than 400 musicians.
The military event began at Horse Guards Parade at 10am and has been part of the monarch's birthday celebrations since the mid-1700s and will feature a fly-past by the RAF at around 1pm.
The Queen was dressed in bright green and was taken to Horse Guards Parade in a carriage alongside husband Prince Philip, who wore a large bearskin.
Prince Harry accompanied the Duchess of Cambridge and the Duchess of Cornwall in another carriage, who both looked glamorous dressed all in white.
The telling off during the fly past was not the first occasion the monarch has put her foot down with her grandson.
Speaking to Sky News for a documentary called The Queen At 90 to celebrate the monarch's birthday in April, the Duke of Cambridge recalled how a childhood telling off stayed with him throughout his life.
Referring to a childhood incident which landed him in hot water with Elizabeth II, William described getting into trouble with his cousin Peter Phillips after riding a quad bike at Balmoral.
He said: "We were chasing Zara around who was on a go-cart, and Peter and I managed to herd Zara into a lamppost and the lamppost came down and nearly squashed her.
"I remember my grandmother being the first person out at Balmoral running across the lawn in her kilt.
"She came charging over and gave us the most almighty b******ing, and that sort of stuck in my mind from that moment on."
However, he went on to reveal the monarch's softer side and credited her with helping him through the loss of his mother, Diana Princess of Wales, and being a powerful female influence in his life.
He said his grandmother had been "incredibly supportive" of him and been someone for him to look up to.
The Duke said: "She's been a very strong female influence and having lost my mother at a young age, it's been particularly important to me that I've had somebody like the Queen to look up to.
"[She's someone] who's been there and who has understood some of the more, um, complex issues when you lose a loved one.
"So she's been incredibly supportive and I've really appreciated her guidance."