Princes Harry and William face torment over a planned Netflix documentary claiming their late mother Princess Diana tried to kill herself four times.
A four-parter provisionally titled Being Me: Diana will tell of her mental health battles, eating disorders, unhappy marriage to Prince Charles and painful childhood.
DSP, the production company behind the James Franco film 127 Hours, has started preparing the controversial project but says it has not yet been commissioned by Netflix.
News of the plans will be a blow to Harry and wife Meghan, who are said to be in talks with the streaming giant over future projects.
Harry also worked with Netflix on a Thomas the Tank Engine 75th anniversary special shown over the weekend.
The series is to use unseen footage from Diana’s speeches in 1990-92 and interviews with people close to her to focus on her inner turmoil just before she and Charles officially split.
A TV source said: “The royals will refuse to take part as will the Spencer family.
“William and Harry will be very upset and angry. It’s particularly distressing for Harry because he’s been working with Netflix.
“At a time when the royals have been dealt a blow with Harry and Meghan leaving, the timing is not good.”
A spokeswoman for Endemol Shine, the parent company for DSP, said: “This is a not a commissioned show and everything within the treatment is already in the public domain.”