Royal documentary Diana: In Her Own Words contained startling revelations, including the bombshell that Diana sought advice from the Queen over Charles' infidelity.
According to the documentary, Diana begged the queen for advice after learning he was having an affair with Camilla.
While speaking to voice coach Peter Settelen, the late princess opened up about the affair.
'I remember saying to my husband, ''Why? Why have you got this lady around?'' And he said, ''Well, I refuse to be the Prince of Wales who never had a mistress,"' she revealed.
She continued: 'So I went to the top lady, sobbing and I said, ''What do I do? I'm coming to you, what do I do?''
'And she said, ''I don't know what you should do, Charles is hopeless''. And that was it, that was help.'
In the recordings, Diana also divulged she that Prince Philip told Charles he could have an affair if his marriage didn't work out.
'My father-in-law said to my husband, 'if your marriage doesn't work out, you can always go back to her (Camilla) after five years',' she said.
'Which is exactly – I mean, for real I knew that it had happened after five (years) – I knew something was happening before that but the fifth year I had confirmation.'
The princess, who tragically died in a car accident in Paris in 1997, also spoke about her battle with bulimia.
'Everybody knew about the bulimia in the family and they all blamed the failure of the marriage on the bulimia, and that's taken some time to get them to think differently,' she said.
'I said I was rejected, I didn't think I was good enough for this family, so I took it out on myself.
'I said, 'I could've gone to alcohol, which would've been obvious, I could've been anorexic, which would be even more obvious. I decided to do the more discreet thing, which ultimately wasn't discreet but I chose to hurt myself instead of hurting all of you'.'
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