The tragic beauty - who died in a 1997 car crash in Paris - was left devastated when, during a heated row, Prince Charles told her he had never loved her and had been given permission by father PRINCE PHILLIP to return to mistress CAMILLA PARKER BOWLES if he was unhappy after five years of marriage.
Diana - who also wrote to Burrell accusing Prince Charles of plotting to kill her - poured her heart out to Burrell and told him she had confronted her father-in-law over the alleged "five-year pact".
In a new chapter, written especially for the paperback edition of Burrell's book A ROYAL DUTY, he writes, "She suspected that Prince Phillip, and perhaps others, had been a collaborating architect in the marriage's downfall.
"That he had given his blessing for Prince Charles to renew his liaison with Camilla. Critics will typically accuse the Boss (Diana) of paranoia in considering that Prince Charles had any sort of blessing to return to Camilla.
"It is worth emphasising now that it was not a figment of her imagination but had been planted in her mind by Prince Charles himself, during a fierce row. In the heat of the moment, Prince Charles told his wife that he had always had his father's blessing - from the outset of the marriage - to return to Camilla if the Princess Did not make him happy.
"The princess had felt like a pawn in a royal game to find a suitable wife for the prince who could not marry Camilla because she was already married.
"In her eyes, she had been sold to the royal family to produce an heir and a spare, in the form of WILLIAM and HARRY, and then returned to the wilderness."27/05/2004 13:37
The film is almost half an hour longer than 'The Force Awakens'.
The actress will no doubt be returning for the long-running FX series.
The film is expected to continue without Mendes' involvement.