Meghan Markle, the Duchess of Sussex, is writing a tell-all memoir that will document her life so far, according to royal expert Tom Bower.

Bower, who is the author of the book "Revenge: Meghan and Harry and the Way Between the Windsors," made the revelation in an interview with Dan Wootton on GB News on Wednesday night.

"My information is that she is writing her memoirs and it will be a huge money-spinner," Bower said. "All that we have seen last week is absolute media manipulation."

Bower's comments come after Meghan made an impromptu speech at the Invictus Games in Dusseldorf on Wednesday night.

In her speech, she hailed the event as "amazing" and joked that she had run slightly late.

"It's so special to be here, and I'm sorry I'm a little late for the party," Meghan said.

Meghan also expressed her desire to bring her children, Prince Archie and Princess Lilibet, to the Invictus Games in the future.

Bower's comments about Meghan's memoir are the latest in a series of negative assessments of the duchess by the royal expert.

In his book, Bower alleged that Meghan had "manipulated" Harry into leaving the royal family and that she was "a demanding diva" who was "difficult to work with."

Meghan's memoir is not yet scheduled for release, but it is expected to be a major publishing event.

If Bower's assessment is correct, the book could be a major money-maker for Meghan and could also shed new light on her time in the royal family.

Meghan Markle's memoir is reportedly being published by Penguin Random House, the same publisher that released Prince Harry's memoir, "Spare."

The book is said to be worth up to $15 million, making it one of the most lucrative tell-all memoirs ever written.

Meghan Markle has not yet commented on the reports that she is writing a memoir. The book is expected to be released in 2023.