The singer added the experience haunted him, linking Dodi’s well-known paranoia about kidnappings and high-speed travel to his and Diana’s fatal crash in Paris.

“One of Dodi’s problems was that he was very paranoid… that’s why he always went fast whenever he got into a car. Fast, fast, fast,” Anka wrote. “Then I started wondering, ‘What if I hadn’t loaned Dodi the money?'”

A source said: “Paul is going to go to his grave with this regret.”

The singer, whose lyrics for Frank Sinatra’s My Way have become iconic, has spent decades observing celebrity excess, including the tragic self-destruction of Elvis Presley and Sammy Davis Jr.

“Basically, Elvis destroyed himself. It got to the point where he’d only see me in his suite, where he had aluminium foil on the windows because he never wanted to see daylight,” Anka recalled.

Similarly, he observed Sammy Davis Jr. spiraling through substance abuse, gambling, and personal excess.