LONDON — Princess Diana's famous "revenge dress" went on public display in London on Friday, days after fresh claims emerged about King Charles' reaction to her death — a reminder that the shadow cast over the royal family by the so-called "people's princess" lingers nearly 30 years on.

The gown became an emblem of the bitterness between Charles and Diana during the public unraveling of their marriage in the early 1990s, when she stepped out in the off-the-shoulder black silk number shortly after Charles admitted his infidelity.

Scrutiny of the couple's troubled relationship resurfaced this week with extracts from a forthcoming book by Diana's brother, Charles Spencer, who accuses the king of sounding "giddily elated" in the immediate aftermath of her death. Buckingham Palace has pushed back against the claims, suggesting the author's memory has been affected by his loss.

A daring dress

The dress was unveiled at Sotheby's, the first stop on a world tour that will take it to Hong Kong, Geneva, and New York — an itinerary underlining Diana's enduring and global allure. It will be auctioned at the final stop in December, with a guide price of between $150,000 and $300,000. The route gives audiences across Asia, Europe, and North America a chance to see the gown in person before it changes hands at auction.

Diana wore the dress in 1994, an appearance widely seen as a show of strength as the public feasted on details of the royal couple's separation — an appetite that has come back strongly this week. Humiliated by her husband's affair with Camilla, whom he went on to marry in 2005, Diana opted for an outfit she had kept in her wardrobe for years but had previously considered too daring.

"We can imagine it's a night where she had to decide — whether I go and what do I wear?" Morgane Halimi, global head of Handbags and Fashion at Sotheby's, told Reuters.

"So she decided to wear something that would make her look the most beautiful, the most powerful," Ms. Halimi added. "It's about being self-assured, being empowered, and not only the negative part of the revenge, but really this is my life and I stand up for myself."

'Her story will never die'

As crowds arrived to view the dress on Friday, Spencer's claims dominated newspaper front pages, broadcast airwaves, and pub talk across Britain — underscoring the challenge facing the 77-year-old king, who has never quite shrugged off his role in a toxic marriage blamed for damaging the hugely popular Diana.

"Everybody liked her, so her story will never die," Merete Lund Jensen, a 54-year-old pediatric nurse, told Reuters.

Beyond her sense of style, Diana was known for the easy affection she showed when meeting homeless people, children in hospital, and AIDS patients — a natural warmth that contrasted with the more formal approach of King Charles.

Diana was 36 when she was killed in a car crash in Paris in 1997, leaving Princes William and Harry, then aged15 and 12, without a mother. Her divorce from Charles had been finalized a year earlier.

At the time, her death plunged the monarchy into crisis. The royal family's stiff upper lip was so at odds with the nationwide outpouring of grief that it caused widespread public anger, forcing the institution to change tack and begin showing the emotion the public expected.

Palace rebuke

Spencer's allegation that the king was "gidd elated" over Diana's death has been rejected by Buckingham Palace in unusually strong terms.

The claims land at a delicate moment for the king, who continues treatment for cancer while trying to repair his relationship with his semi-estranged son Harry and navigate the fallout from the arrest of his younger brother, Andrew Mountbatten-Windsor. The next fixed dates in the story are the book's full publication on Tuesday and the gown's December auction in New York.

The book, which is being serialized in the Daily Mail and will be published on Tuesday, claims Charles said of Diana: "we'll forget her soon enough."

Her brother writes: "Unlike my other callers, who were stunned, barely able to articulate their condolences and offers of help, he sounded giddily elated — like a lottery winner, I remember thinking at the time."

A Buckingham Palace spokesperson said on Wednesday: "While we do not comment on books as a matter of principle, His Majesty is mindful that the pain of fraternal grief can cloud reason, affect judgment and color memory in ways others do not recognize, even many years after such a loss."

Royal commentator Afua Hagan said the palace's reaction showed that, 29 years after Diana's death, the royal family remains out of touch with how well-loved she continues to be.

"I do think it was quite cold, quite aloof, and that kind of harks back to what people said about the royal family in those days after Princess Diana died. It's definitely not a good look," she told Reuters.

— Reuters