Kate Middleton - the Duchess of Cambridge  -  was left devastated and deeply affected after Prince William and Harry's fallout, claimed royal insiders.

Kate's hubby and Meghan's sweetheart's relationship has been strained since the Duke and Duchess of Sussex decided to leave royal duties behind.

Harry and William's fallout is also said to have "deeply affected" Kate, the Duchess of Cambridge, who was left "devastated" by the feud according to one royal expert.

The Duke of Sussex is set to release his memoir next year, promising to be an "accurate and wholly truthful" account of his life.

However, Prince William is said to be concerned by the news, and one royal expert had claimed Harry's new project could be especially damaging for his brother.

Ingrid Seward, editor-in-chief of Majesty Magazine, said this week that Harry could say "inappropriate things" about the Firm, with terrible consequences for William.