A New Hampshire auction house is to offer a rare photograph of the young Princess Diana that has "not to be published" scrawled across it in an editor's hand.
The remarkable photograph, which was once part of the archives of the Daily Mirror newspaper, will be offered with a minimum bid of just $200. Its pre-sale estimate is $1,000, though it is expected to sell for more when bidding closes on January 24.
The auction house's Bobby Livingstone told Paul Fraser Collectibles: "In an auction, you can never tell where these things might end up."
The photograph - showing Diana reclining with a man and a bottle of whisky at her side - is dated February 26, 1981 on the reverse, just two days after the announcement of her engagement to Prince Charles.
However, the photograph is believed to have been taken during a skiing trip in 1979, a year before she and Prince Charles became romantically linked.
Livingstone and his team initially believed the unidentified man to be Diana's brother, Charles Spencer.
The man has since been established as her friend Adam Russell, the great-grandson of British prime minister Stanley Baldwin.
Livingstone explains that publication was halted not because of the presence of Russell, but for an entirely different reason.
"Because of the date on the back of it, two days after the announcement of the engagement, the editor decided not to run that photo - not with a Johnnie Walker bottle in the background," he said.
Having been consigned from the Caren Archive, which purchased the Daily Mirror's archives around seven years ago, the photograph has likely never been seen by the public before and will undoubtedly see strong results.
On the enduring appeal of Princess Diana collectibles, Livingstone commented: "Diana has always been one of those figures that we get intense interest for, prices are always very strong for premium Diana memorabilia."
Paul Fraser Collectibles has a fantastic selection of Princess Diana memorabilia available, including a classic example of her inimitable style and a handwritten and signed letter, written to one of her closest friends.