Friends of Princess Diana have urged Channel 4 not to broadcast controversial video tapes of her talking about her troubled marriage.
The documentary, Diana: In Her Own Words, is due to be aired ahead of the 20th anniversary of her death.
The tapes, recorded by her speech coach, have never been seen in the UK.
Channel 4 said they “provide a unique insight” – but Diana’s close friend Rosa Monckton said they were a betrayal of the late princess’s privacy.
Mrs Monckton is writing to the broadcaster to ask them not to air the tapes. She told The Guardian: “This doesn’t belong in the public domain.
“It is a betrayal of her privacy and of the family’s privacy.”
The footage was recorded by Peter Settelen, who was hired by the Princess of Wales between 1992 and 1993 to help with her public speaking voice.
She was filmed at Kensington Palace and is seen talking about her marriage to the Prince of Wales, their sex life and how she confronted him about his affair with Camilla Parker Bowles, now the Duchess of Cornwall.