Newly released audio clips of Princess Diana have been heard for the first time (Picture: Bettmann Archive)

Never heard before audio tapes of Princess Diana have been released for the first time – and they’ve revealed a whole host of truths.

Her most intimate thoughts were recorded more than 30 years ago in a conversation with close friend James Colthurst.

She later gave the tapes to her biographer and author Andrew Morton in secret in the 1990s.

He then used the audio clips to write his bestselling book Diana: Her True Story.

Snippets of the recording obtained by ABC in the US, just one day after the 26th anniversary of her death, give a first-hand insight into her life – all in her own words.

And in the tapes, which will form part of a new documentary set to be released next year, Diana revealed her honest opinion about her marriage to the now King Charles.

Discussing her wedding with Charles in July 1981, she’s heard describing it as ‘ridiculous’.

The Prince and Princess of Wales return to Buckingham Palace by carriage after their wedding on July 29, 1981 (Picture: Getty Images)

In one clip, she says: ‘It was so grown up. And here was Diana, a kindergarten teacher. I mean the whole thing was ridiculous.’

The tapes also unveiled discussions she had about her troubled relationship with her stepmother Raine Spencer, who married her father John in 1976 after her mother Frances had left.

Recalling what happened after Prince Harry was born, Diana said: ‘My husband won’t even talk to mummy… barely.

‘Because at Harry’s christening, Charles went up to mummy and said: “You know, we were so disappointed, we thought it would be a girl.”

‘And mummy snapped his head off and said: “You should realise how lucky you are to have a child that’s normal.”

‘Ever since that day, a shutter’s come down and that’s what he does when he gets somebody answering back at him so to speak.’

Princess Diana pictured with her stepmother Raine Spencer, with whom she had a troubled relationship (Picture: Getty Images)

Diana admitted her brutal honesty towards Countess Spencer and how she felt about her following her father John’s death in 1992.

She can be heard saying: ‘I was so angry and I said, I hate you so much. If only you knew how much we all hated you for what you’ve done.

‘You’ve ruined the house, you’ve spent daddy’s money. I said everything I possibly could and Raine said “you have no idea how much pain your mother put your father through”.

‘I said: “Pain, Raine? That’s one word you don’t even know how to relate to.”

‘In my job and in my role, I see people suffer like you’ve never seen. And you call that pain? I said: “You’ve got a lot to learn.”

‘I remember really going for her gullet.’

Audio clips of Princess Diana discussing her wedding to Charles and relationship with her stepmother Raine Spencer have been released for the first time (Picture: Getty Images)

Raine eventually left the family seat of Althorp because of the strained relationship she had with Charles and Diana.

Diana and her siblings reportedly referred to their stepmother as ‘Acid Raine’.

Tom Jennings, the producer of both a previous 2017 documentary and the upcoming one, told ABC: ‘When the first film came out, people were blown away because they had not heard Diana talk like this before.

‘It’s a style of storytelling that is very difficult to do but I think it is the closest thing to the truth that you can get because nothing gets in your way.

‘It is important as part of Diana’s legacy to allow more of those tapes to be heard.’

Seven hours of audio were recorded in total by Diana while she was still married to King Charles, who was the Prince of Wales at the time.

Not all of the audio was heard in the 2017 documentary, however, meaning it will be the first time this has been publicly shared.

Princess Diana was killed in a car crash in a tunnel in Paris, France on August 31, 1997 while the driver was fleeing from the paparazzi.

The newly heard audio tapes also come just one week before the anniversary of the death of Queen Elizabeth II, the mother to King Charles.