Camilla’s path to becoming queen was a triumph of image transformation.

The coronation will mark the formal ascension of King Charles III as the British head of state and Defender of the Faith. But it is also a triumph of image transformation, with his wife, Camilla — who was vilified for years in the British news media — crowned as queen.

While Charles’s crowning has long seemed inevitable, the public’s acceptance of Camilla — let alone her holding the title of queen — once seemed extremely unlikely. In the public’s eye, she was cast as the villain who broke up Charles’s marriage to his first wife, Diana, the Princess of Wales, who died in a car crash in 1997. And intimate details of Charles’s and Camilla’s relationship have long made for tabloid fare.

Some historians and public image consultants say the speed of her metamorphosis is staggering.

“There was that moment after Diana’s death when most people said, ‘We can’t have Camilla,’” said Jennifer Purcell, a professor of modern British history at Saint Michael’s College in Vermont. “‘First, we don’t want him to marry her. Second of all, if he does marry her, then she should never be queen.’”

Tell-all interviews and the publication of a tapped phone call between Charles and Camilla — the graphic details of which had faded from the nation’s contemporary collective memory but were recently revived for watchers of “The Crown” — brought out embarrassing details of the pair’s private life splashed across front pages.

That is all in the past now.

Camilla’s branding overhaul has been a huge effort, said Cele Otnes, a professor and co-author of “Royal Fever: The British Monarchy in Consumer Culture,” that began long before Camilla’s marriage to Charles.

“It’s not just his coronation, it’s their coronation,” Professor Otnes said. “We are now understanding Charles and Camilla as a brand just as we understood the queen and Prince Philip as a brand. And I think that is a strengthening factor for them both.”

In the nearly two decades since her marriage to Charles in 2005 — after both of their divorces and the subsequent death of Diana — the new king and queen have cultivated their personas with a focus on public service, the stability of their relationship and, above all, discretion.

“Now, even if people may not like it, they are accepting of it,” Professor Purcell said. “She’s just done a great job at hanging in there and trying not to make missteps.”

In the latest polls on the royal family’s standing among the British public from the analytics group YouGov, Camilla outranks both Prince Harry and his wife, Meghan.

Queen Elizabeth II is partly responsible for the public acceptance of Camilla as queen. At the time of her Platinum Jubilee last year, she cleared a path for her daughter-in-law with a public letter expressing her wish that Camilla would become queen consort when Charles ascended to the throne, putting to rest years of uncertainty.

“With the royal family, especially if you think of it as a brand, there are so many recent examples of tainted-ness,” Professor Otnes said, pointing to Prince Harry’s very public airing of the family’s dirty laundry and Prince Andrew’s settling of a sexual assault lawsuit. “Camilla is not one of those examples anymore. She is now on the value-adding side.”

Still, the seven months since the death of Elizabeth, Britain’s longest-serving monarch, haven’t been entirely trouble free for the soon-to-be-crowned queen. In his widely publicized memoir, “Spare,” and the series of interviews promoting it, Prince Harry singled out Camilla for some of his most cutting comments, accusing her of planting negative stories about him in the press to boost her own image.

He also criticized his stepmother and father in a recent legal filing as part of a lawsuit against Rupert Murdoch’s News Group Newspapers. Harry accused the tabloids of intercepting his calls for many years, and later reneging on an agreement with the royal family to apologize, but also laid out a secret agreement between the family and the publisher.

He expressed frustration over that agreement and said the staff of his father and Camilla “had a specific long-term strategy” to keep the news media on their side, “to smooth the way” for Camilla’s acceptance.

Arianne Chernock, a professor of history at Boston University who is an expert in the modern British monarchy, said that despite the most recent vitriol, Camilla had already shown an ability to draw on her own complex past to forge a new identity.

“It’s surmountable,” Professor Chernock said, “but that’s more baggage that Camilla carries with her into this role as she tried to cement her position as queen, establish herself and set this tone for what their kingship and queenship are going to look like.”