Buckingham Palace took the unusual step of publicly questioning Charles Spencer's recollection of a conversation with King Charles III after Princess Diana's death, responding forcefully to an allegation in Spencer's forthcoming memoir that the then-Prince of Wales said his former wife would soon be forgotten.

The intervention was notable because the royal household generally avoids detailed responses to memoirs and personal accusations. Rather than simply denying the account, the palace suggested that Spencer's memory of events nearly three decades ago may have been affected by grief.

"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," the palace said Wednesday.

The statement was issued after excerpts emerged from Spencer's Swan Song: Diana, My Sister, due to be published next week. The book revisits the days following Diana's death in a Paris car crash in August 1997 and describes an alleged confrontation between her brother and Charles over the funeral arrangements.

At the center of the dispute was whether Princes William and Harry, then 15 and 12, should walk behind their mother's coffin. Spencer writes that he objected because he believed Diana wouldn't have wanted her sons subjected to the emotional burden and public attention of the procession.

According to Spencer's account, Charles responded with what he described as a "stream of anger." Spencer alleges that Charles then said: "Rest assured, we'll forget her soon enough."

The palace disputes that characterization. BBC reporting cited by The Hollywood Reporter said royal officials viewed the alleged comment as entirely inconsistent with Charles's character and with the circumstances at the time, when he was dealing with his own grief while supporting William and Harry.

The response also recalls an earlier strategy used by Queen Elizabeth II. After Prince Harry and Meghan, the Duchess of Sussex, made allegations about racism within the royal family in 2021, the late queen responded that "recollections may vary," a brief formulation that challenged the account without entering into a prolonged public argument.

Diana's funeral remains one of the defining moments of the modern monarchy. Spencer, William and Harry ultimately walked behind the coffin through central London, while the royal family faced intense criticism over what many members of the public regarded as an initially restrained response to Diana's death.

Her death at age 36 came a year after her divorce from Charles and triggered an extraordinary global outpouring of grief. Diana had become one of the most photographed and recognizable women in the world after marrying Charles in 1981.

India McTaggart, a royal correspondent at The Telegraph, told NBC News that the palace may be trying to address damaging allegations before more excerpts from Spencer's memoir emerge. She said the book is expected to contain additional contentious claims.