CHARLES Spencer has marked the anniversary of his sister Princess Diana’s death with a starkly simple message — and news of a new book told from his side of the story.

On August 31, 2026, Spencer posted on Instagram: “31 August. My least favourite day,” alongside photos showing a flag flying at half-staff over Diana’s childhood home, Althorp House, in the UK.

Ahead of the anniversary, Spencer also announced Swan Song: Diana, My Sister, set for release on September 22, 2026. He said the book’s aim is “to tell the truth about Diana from her brother’s perspective,” adding that he wants to speak on her behalf “in an openly positive way,” as he did when he delivered his funeral eulogy.

Spencer added that he hopes the book connects with people who still remember Diana in life — and helps those who were too young at the time understand “who she really was,” describing her as “a one-off, dynamic character, full of love, charisma and self-doubt.”

Diana, born July 1, 1961, married then-Prince Charles in July 1981 and became a mother to Prince William (born 1982) and Prince Harry (born 1984). After years of widely documented strain, the couple separated in December 1992 and finalised their divorce in August 1996.

Diana died on August 31, 1997, after a car crash in Paris while trying to evade photographers. Dodi Fayed and the driver, Henri Paul, were also killed. William and Harry were 15 and 12 at the time, and have continued to honour their mother’s legacy in the years since.