Charles Spencer to 'tell the truth' about Diana, Princess of Wales in new book

Charles Spencer has promised to "tell the truth" about his late sister, Diana, Princess of Wales, in a new book.

On Tuesday, editors at Penguin Press announced that the British peer and author will publish a memoir titled Swan Song: Diana, My Sister on 22 September.

In a statement, Charles explained that he had been "convinced" to write down his "own thoughts and memories" of his older sibling ahead of the 30th anniversary of her death.

Tragically, Diana died at the age of 36 in a car crash in Paris, France in August 1997.

"The aim of this book is to tell the truth about Diana from her brother's perspective, just as I attempted to do when speaking at her funeral. As with my eulogy, I want to speak on Diana's behalf and do so in an openly positive way," he said, referring to the emotional speech he delivered at the funeral service for the royal held at Westminster Abbey in September 1997.

Charles went on to note that he hopes the book will be interesting to the people who still "cherish" memories of Diana when she was alive.

"I would be delighted if those too young to remember her in her heyday feel, after reading this, that they 'get' who she really was: a one-off, dynamic character, full of love, charisma and self-doubt, who gave life a hell of a go, and left the world a far better place, despite exiting the stage while still so young," the 62-year-old added.

Swan Song marks the "first time" Charles has spoken "openly" and at length about his sister.

And Daniel Bunyard, publishing director at Penguin Michael Joseph, emphasised that the book contains "many revelations that will draw considerable attention" but also serves as a "fitting tribute".

Diana was the first wife of Charles, Prince of Wales, now King Charles III, and the mother of Prince William and Prince Harry.