A previously unseen image of then-20-year-old Diana Spencer pictured with an unidentified man two days after the announcement of her engagement with Prince Charles is up for sale at an auction. A London tabloid once deemed it too hot to print.

The black-and-white photo from the early 1980s shows Diana smiling at the camera as she lies in the lap of an unidentified young man reading a book, with a bottle of whisky standing by the window.  

The words "not to be published" are written across the 20x25-centimeter photo, dated February 26, 1981 on its back – two days after Buckingham Palace announced the engagement of Prince Charles and Diana Spencer.

Bobby Livingstone of RR Auctions of Amherst told AFP that the photograph would typically sell for around $1,000, "but because it has that [not-to-be-published] marking on it, we expect it to go for much more."

"It captures the moment when the engagement had been announced two days before and the press was going mad over Diana but the Daily Mirror just wasn't going to publish this picture of her in a comfortable position with a man other than Prince Charles," he said.

Internet bidding on the photo will run from January 17 to 24.

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