The book by Prince Harry will be titled Spare and will include his full account behind his decision to give up royal duties and move to the US.

Random House said: "As Diana, Princess of Wales, was laid to rest, billions wondered what the princes must be thinking and feeling - and how their lives would play out...

"For Harry, this is his story at last."

Buckingham Palace said it would not comment on the book announcement.

Some of the proceeds from the book go to charity. The publisher confirmed this was in the form of two donations of $1.5m (£1.3m) and £300,000 respectively to the charities Sentebale and WellChild.

Sentebale, co-founded by Prince Harry in 2006, helps children and adolescents in Lesotho and Botswana struggling to come to terms with their HIV status. WellChild is a British charity that gives grants so young people with exceptional health needs can be cared for at home instead of in hospital.

When the deal for Prince Harry to write his story was announced in 2021, the prince promised he would reflect "the highs and lows" and be "accurate and wholly truthful".

In its press release for the 38-year-old's memoirs, Random House said: "Spare takes readers immediately back to one of the most searing images of the twentieth century: two young boys, two princes, walking behind their mother's coffin as the world watched in sorrow and horror."

Prince Harry, 12 at the time, attended his mother's funeral with his father and brother after her death in a car crash in Paris in 1997

Prince Harry and Meghan attended Queen Elizabeth II's state funeral in London on their most recent visit to the UK

That theme is picked up in the publicity statement for the book, which says: "With its raw, unflinching honesty, Spare is a landmark publication full of insight, revelation, self-examination, and hard-won wisdom about the eternal power of love over grief."

The book will be published on the same date worldwide and it will be available in 16 languages.

The audio edition of the book is read by Prince Harry.

The Duke and Duchess of Sussex announced that they would step back from royal duties and work to become financially independent in 2020. At the time, Buckingham Palace and senior royals expressed their disappointment and hurt at the announcement.

Harry and Meghan now live in the US with their two children, son Archie and daughter Lilibet.

The publisher's description of the book's author, which is likely to appear in the book, reads: "Prince Harry, the Duke of Sussex, is a husband, father, humanitarian, military veteran, mental wellness advocate, and environmentalist. He resides in Santa Barbara, California, with his family and three dogs."

In June, Prince Harry was seen playing polo in Santa Barbara