© RR Auction COAThe 10 x 8 glossy news photo of a young Diana lying in bed with a young man seated behind her
The question of her companion's identity was solved last night when it was confirmed to be Adam Russell, an Old Etonian and the great-grandson of former Prime Minister Stanley Baldwin.
The picture, to be sold at auction in America later this year, is thought to have been taken in 1979 or 1980, and despite the intimacy it depicts, Mr Russell was said to be "just a friend" of Diana's.
The pair had been injured on the same ski trip and were relaxing togather when the photo was taken.
Had "smitten" Mr Russell made his feelings about her known sooner, the whole future of the British monarchy could have been very different, it was suggested.
Andrew Morton, the royal biographer, told ITV News: "They kept each other company while the others went skiing and at the end of the holiday Adam was somewhat smitten but absolutely nothing happened.
"He left unspoken the fact that he hoped the friendship between himself and Diana could be renewed and developed upon his return.
"When he arrived home a year later it was too late. A friend told him: 'You've only got one rival - the Prince of Wales."
Mr Russell is now believed to be a deer farmer living in Dorset.
The picture was sold to the Daily Mirror in 1981 two days after Diana's engagement to Charles was announced.
The newspaper chose not to use the picture - hence the instruction "not to be published" scrawled across it.
Princess Di - as I said when the news came through, (having grown up in a place where dark, macabre humor is S.O.P.), "Well for once, someone lived up to their name."
I can't be the only one, though.
R.C.