In his new book David Bowie by Denis O'Regan, the famed photographer takes a heartfelt and meticulous look back at touring with the iconic singer over three decades — in the 1970s, at the end of his ...

Princess Diana Archive/Getty Princess Diana and David Bowie at Wembley Arena in London for the Concert of Hope on World AIDS Day on Dec. 2, 1993.

Princess Diana and David Bowie at the Concert of Hope benefit for World AIDS Day at Wembley Arena in London on December 2, 1993. | Credit: Tim Graham Photo Library via Getty Images ...

Never before seen pictures of Princess Diana and David Bowie have been discovered 40 years after they were taken. The images were 'buried' after photographer Denis O'Regan received a 'polite ...

Princess Diana Archive/Getty Princess Diana and David Bowie at Wembley Arena in London for the Concert of Hope on World AIDS Day on Dec. 2, 1993. Can't get enough of PEOPLE's Royals coverage?

The photographer made the revelation in a conversation about his new book David Bowie by Denis O'Regan, which will be published in the U.S. on Aug. 5. The upcoming text from Bowie's official ...