Princess Diana had recorded secret audio tapes in the 1990s giving an unfiltered account of her royal life, which were transformed into the biography "Diana: Her True Story" by Andrew Morton. It has recently been revealed that the royal had feared that her friend, who used to transport Morton's questions to Kensington Palace and Diana's answers back to the author, would be knocked off his bike on purpose on his way.

ITV's recently released film "Diana," marking the late royal's upcoming 60th birthday on July 1, includes the testimony of her friend Dr. James Colthurst who used to deliver her audio tapes to Andrew Morton, reports Mail Online. Colthurst, who met Diana during her teenage years on a skiing trip and became a life-long friend, was one of the very few people who knew about the tapes.

Diana's association with the biography had come as a shock when it was released in 1992, as it marked the first time a senior royal had done a tell-all about their personal lives, giving an unprecedented insight into British monarchy. Her involvement with the book was kept secret in order to avoid any attempt in stopping its release.

Colthurst recalled about their secret operation for the biography, "I'd then hand the tapes over and they were transcribed. I used to cycle them to a restaurant - it's all very covert isn't it, sounds that way...that was the handover point, the live letter box."

Colthurst revealed that the Princess of Wales was paranoid that someone would purposely interfere with the publication of the tell-all. Therefore, every time he was tasked with carrying those explosive secret tapes to a drop-off point in South London, Diana worried that he would be "deliberately knocked off his bike."

"I think I had a great relief each time I handed over a tape. Diana always had a problem knowing this was going on, she was worried I'd be knocked off my bicycle deliberately," he recalled.

He revealed that one of the tensest moments in his secret transportation mission was when he spilled incriminating transcripts right outside the parliament while swerving to avoid a bus.

"They were some pretty anxious moments. Not least when I had one batch of transcripts and I was going through the Houses of Parliament and a bus had moved me over to avoid some traffic I think on to a pothole. I hit it hard and the papers went all over the road right outside the Houses of Parliament so that was an anxious time," he recounted.

Princess Diana
14 April 1986: Princess Diana wears a sequinned blue Catherine Walker gown for a gala at the Vienna Burgh Theatre during a visit to Austria Tim Graham/Getty Images