Earl Spencer sets record straight on Diana memoir: 'Not a threat to King Charles'

Earlier, Buckingham Palace issued a statement denying author Earl Spencer's characterization of his conversation with then-Prince Charles about Diana's death.

But the late princess's brother has now shot back.

In an interview with the BBC, he said he knows “lots of things about the King” but is intentionally holding them back in his upcoming book, Swan Song: My Sister.

“I’m aware of mortality, and I wanted to just put things down once and for all that were true," he said.

However, he clarified, "This is not a threat."

But given the nature of his statement, he was pressed that it does, sound like, a threat.

To this assertion, Spencer pushed back, “No, not at all a threat; it’s just the reality. If I were a salacious writer and wanted to write that sort of thing, I would have plenty of other things I could have said.”

Adding another explanation of not including allegedly incriminating information, Spencer shared that "they were not relevant.”

Then, there is a question about the author being bitter toward Charles, and that is probably his motivation to pen the book.

But Spencer strongly denied this, adding, "I don't hold resentments, primarily because I don't think it's good for the person to do that themselves."

"I've let a lot go. I'm not a vengeful, resentful person. I'm just an eyewitness to history."

Meanwhile, the Swan Song: My Sister will be released on Sept. 22.