Watch: Prince Philip coached Prince William for his future role as King
Prince William may have always known he would grow up to be king, but the duke has spent the last 10 years gradually increasing his public profile and building up a royal portfolio.
He is celebrating his 10th wedding anniversary with wife Kate in a new royal era - one that will be marked by the absence of Prince Philip, his grandfather, and by the huge physical and emotional distance between him and his younger brother, Prince Harry.
In the midst of the turmoil, William is stepping up to show the kind of king he might be, and attempting to modernise the Royal Family.
With changing officials and personnel around him, William has been adapting to fit the modern world, and his strategic comments on social media have been just one example.
In April, he waded into a row about the European Super League, siding with fans as he stated concerns about the plans for a separate league involved six British teams.
In a post on Twitter, he wrote: "Now, more than ever, we must protect the entire football community – from the top level to the grassroots – and the values of competition and fairness at its core.
"I share the concerns of fans about the proposed Super League and the damage it risks causing to the game we love."
He signed off the tweet 'W', showing it was a personal comment from him, and not a general post on his behalf.
William, 38, is careful about how frequently he weighs in with personal opinions. But as a keen Aston Villa fan, he is likely to have followed the plans with interest and wanted to show support for fans of all teams.
Of the comment, PR expert Anthony Burr said: "William is positioning himself in a way that we haven’t seen before, especially after the gulf that has grown between him and his brother.
"Ever since Meghan and Harry’s explosive Oprah interview, we have seen a different side to William. It seems to be very strategic.
"Getting involved in the European Super League argument was a good move. He is, after all, President of the FA, so it was well-advised to make a comment and a powerful one at that. Another power-play was the Earthshot letter, co-signed by a host of global celebrities and superstars – this is a project close to his heart."
He added: "These ‘W’ statements are also a clever move. We have the personable, affable touch with humanises him, whilst also subtly detaching him from 'The Firm' as an institution.
"This is potentially the start of a new brand he is designing for himself, a more modern royal. And that is a good thing."
While Prince Philip's funeral was a deeply sad moment for the Royal Family, it also presented both William and Kate with opportunity, to begin to heal the rift between brothers, and to give an impression of leadership within the royal family.
The result was a bounce in their popularity. A poll for YouGov after the funeral found that both William and Kate were seen more positively by the British public.
Nick Ede, popular culture and brand expert, told Yahoo UK: "I feel that Prince William is taking a lead in a really strong and impressive way - he is clearly building his own personal brand, which will resonate well with many people.
"He is showing his opinions and using social media and the media in general to do so.
"He is using these platforms to command attention and make pointed comments about things that he is clearly passionate about, namely, the environment and football.
"This has seen him appeal to a lot of people, who can see he keeps the people of the UK and beyond in his heart and forefront in his mind, with a view that one day he will be King. I think that this use of his brand and social media – and the media in general – is a very clever way of getting people to see the Royal Family, and him especially, as allies and supporters, here to create positive change for good.
"The more he does this, the more his popularity will rise and he will appeal to even more people worldwide and especially in the UK."
Much has been said about the Royal Family's intent to 'slim down' the monarchy, with Charles said to be spearheading a smaller group of royals who could be seen as better 'value for money'.
It may never have been Charles's intent that his second son Harry wouldn't be part of that, but the Duke and Duchess of Sussex have made it clear they see their future in California and not the UK.
Burr said: "Despite the recent turmoil of the last few months surrounding the negative publicity with his brother and the passing of his grandfather, we more often than not see William as a smiling, ebullient character. His wife is his perfect partner and their carefully crafted publicity shots of their young family are definitely striking a positive chord with the public.
"The growing army of British republicans wishing for the Royal Family to be disbanded have got a problem whilst William and Kate continue to poll well. They are the great hope for The Royal Family."
Watch: William and Kate's fairytale wedding