In Her Own Words utilises private video footage Diana made as part of a course of speech coaching, claiming the confessional nature of what was filmed - including conversations about Diana's sex life with Prince Charles - amounted to therapy.
Channel 4 say the tapes offer an "important contribution to the historical record" about the princess.
Back in 1993, Princess Diana and her public-speaking coach Peter Settlen had chose to record her so that she can watch it and learn from it.
'This unique portrait of Diana gives her a voice and places it front and centre at a time when the nation will be reflecting on her life and death'.
In the recordings, Princess Diana talks about having little affection from her parents as a child.
She once sought comfort from the Queen, "So I went to the top lady and said: 'I don't know what I should do.' She said: 'I don't know what you should do.' And that was it". He was all over me and I thought, you know, "Urgh". The recordings were made by Peter Settelen, a voice coach, when he was helping Diana with her public speaking techniques.
In the video recordings - aired in a U.S. documentary 13 years ago but never screened in the United Kingdom - a relaxed and candid Diana said: "My father-in-law said to my husband "if your marriage doesn't work out, you can always go back to her after five years".
The recorded tapes of Diana's session with Mr Settelen were returned to his keeping in 2004 after a lengthy dispute with Diana's family, headed by Earl Spencer, who said the footage belonged to them.
Both former royal employees credit Diana with "changing the face of the British monarchy", breaking its "theatre" to engage with hard-hitting issues of public life and, most importantly, passing that legacy onto her sons.
ABC and People magazine team for this two-night special featuring an exclusive USA interview with Earl Spencer, Diana's brother Charles.
The broadcast of Diana: In Her Own Words may well prove to be particularly devastating for the heir to the throne, prince Charles, whereas Lady Di comes back that hold the torments of her marriage with one whom she had met only thirteen times before the big day and with whom sexual relations were reduced to the strict minimum.
"This is just another way of exploiting Diana", she said.
These tapes have been highly-contested since being discovered in 2001 at the home of Paul Burrell, the former royal butler.
Speaking on his LBC show, James said: "Prince Harry seems to me to have grown up to become a really impressive young man".
Princess Diana's ballet teacher, Anne Allan, also opened up about how Diana felt about Charles being disloyal to her.
And she adds that the royal family knew about the bulimia that she suffered at the time.