In my job, someone asks me almost every day: “What is the royal family really like?” More often than not, before I’ve had the chance to answer, they deliver a verdict: “Harry’s the fun one, isn’t he? The heart-on-his-sleeve guy. William’s the more serious, sensible one.”

In a charming, informal, revealing wander around Windsor with the actor and comedian Eugene Levy, of Schitt’s Creek and American Pie fame, the Prince of Wales has sought to gently shift that narrative.

The interview for Levy’s series, The Reluctant Traveler, which aired on Friday, may have been produced by Apple TV+’s “unscripted” department, but it was anything but for William.

The future King — who swung into Windsor Castle’s quadrangle, not in the state Bentley as his father often does but on his electric scooter — came very much prepared with what he wanted to say, and the markers he wanted to put down. It was the future Scooter King’s manifesto for monarchy: “Change is on my agenda. Change for good. I don’t fear it.”

Timing is everything. For some time now, the next in line has been keen to “socialise” what the future reign of William V will look like, while ever-conscious of not queering his father’s pitch.

How Prince William will change the monarchy, by those close to him

Before his 43rd birthday in June, I wrote of how the previous year had been the most formative of his life in thinking about and planning for his future role, as he navigated the curveballs of the King and the Princess of Wales’s cancer diagnoses. He was, a friend told me, keen to explore the make-up of the institution and ensure that it’s “fit for purpose”.

Last week, while joking with Levy that “if you want to know about history, I’m not the guy”, the next King let us know exactly what he thinks about history when it comes to decision-making.

Eugene Levy and Prince William walking outside at Windsor Castle with a black dog.

The prince and the actor walked Orla the cocker spaniel in the castle grounds

IAN GAVAN/APPLETV+/PA

Under the last reign and the current one, decisions have often been made based on traditions established over centuries. William is calling time on that. As he told Levy: “If you’re not careful, history can be a real weight and an anchor round you, and you can feel suffocated by it, and restricted by it too much … tradition has a huge part to play in all of this, but there’s also points where you look at tradition and go ‘is that still fit for purpose today? Is that still the right thing to do? Are we still doing and having the most impact we could be having?’ I like to question things.”

The contrast between the current Carolean era and the winds of change signalled by the future William V were tangible last week, as I watched Charles, 76, on manoeuvres in Scotland for his King’s Foundation charity at Dumfries House in Ayrshire.

Dapper in his grey suit and pocket handkerchief, sipping tea from a crested, gilded cup and saucer and making polite, encouraging conversation with young artisans in the Tapestry Room of Dumfries House, Charles’s world felt light years away from the screening of William’s interview that I had just watched in a hotel in Soho.

In a navy “shacket”, wearing trainers for a dog walk with Orla, his cocker spaniel, William and Levy are shown going to The Two Brewers in Windsor and having a pint (cider for William, Guinness for Levy) while the prince regaled him with tales of his university pub-crawl days at St Andrews.

The prince wanted us to know that he has been to some “pretty, you know, not great places” after having the “metaphorical rug pulled” from under his feet with his father and wife’s illness.

By his own admission, the idea of the top job no longer overwhelms William, but “worry or stress around the family side of things, that does overwhelm me quite a bit … because it’s more personal, it’s more about feeling, it’s more upsetting the rhythm”.

Clearly emotional, the heir did not name the self-proclaimed “spare” at this point. He didn’t need to. Harry is still family, his absence still stings William.

“For me, the most important thing in my life is family,” said William, as he put down another significant marker with Levy, justifying why he chooses not to work a “nine to five” day. He may often top royal popularity polls, but there has historically been a question mark over his work ethic humming under the surface. His father and his aunt, Princess Anne, clock up far more engagements than him, year in, year out.

In a deft explanation, laden with just enough honesty and emotion about his own experiences of growing up in a broken home following his parents’ separation when he was ten, William set out his case for being a hands-on father to Prince George, 12, Princess Charlotte, ten, and Prince Louis, seven. They eat together on as many nights as they can manage, he said, and both William and his wife try not to work during the children’s school holidays.

“Everything is about the future and about if you don’t start the children off now with a happy, healthy, stable home, I feel like you’re setting them up for a bit of a hard time and a fall … you try and make sure you don’t make the same mistakes as your parents … I just want to do what’s best for my children.”

There are plenty of unanswered questions about what changes William will make to the monarchy. Much of his manifesto is still a work in progress, and he hopes it will be many more years before his time comes.

Explaining to a slightly bemused Levy that “we don’t actually live in the castle itself, but we come and use the castle for work and for meetings and see people”, that’s one conundrum William needs to crack on with. However modern and “relevant” a monarch he plans to be, if palaces and castles are no longer to be the home of the sovereign, what — and who — are they for?

Eugene Levy and Prince William at Windsor Castle.

Levy was bemused to find that the royal family doesn’t live in the castle

IAN GAVAN/APPLETV+/PA

Eugene Levy and the Prince of Wales at Windsor Castle.

But for now, as Levy surmised at the end of the programme, it doesn’t matter. William has just given us a window into his soul, and many viewers will relate to what they see. “You know what really struck me today?” said Levy. “We’re all sweating the same stuff — work, health, family — and that’s true, even for a future King … I kind of hope that when William becomes King, I’ll still be around to tell my grandson: ‘See that guy wearing the crown? I had a pint with him once.’”

As one of William’s closest friends told me, it’s mission fulfilled on that front: “Delighted that people get to see PW [Prince William] as he is behind the scenes.”