The bicycle which Diana rode to work as a nanny before she married Prince Charles is going up for auction.
Then-Lady Diana Spencer, the royal was told the bike was "unfit for a princess" so had to sell it before she got married in 1981.
She used to use it to get to work as a nanny when she lived in Earl's Court, but was told it was not appropriate by royal officials.
According to one newspaper cutting, Diana once revealed she used to lock the bike to the gates outside her flat, and on one occasion, found one of her wheels had been stolen.
The bike, a blue Raleigh traveller, was last sold in 2018 for £9,200.
It will go under the hammer at Burstow and Hewett Auctioneers in Battle, East Sussex, on 28 April, and is expected to fetch much more than that given a recent rise in interest in royal memorabilia.
Sharing details of the lot, the auctioneers explained: "Branded the 'shame bike', this item is a famous symbol of Diana’s oppression.
"Something she loved being taken away; and control over her public appearance for the reputation of what is deemed acceptable for a lady of the British Royal Family."
They continued: "With most recent headline news surrounding Meghan Markle, The Duchess of Sussex and her treatment by the press and Royal Institution; comparisons have been made between her experience and that of The People’s Princess Diana.
"There is no doubt that this, in conjunction with the popularity of The Crown series, could see the bike selling well above."
The bicycle is being sold with a newspaper article from 1981, the year she was told to stop riding the bike, and a framed letter from Gerald Stonehill, who first bought the bike from her.
Stonehill said: "Diana had hoped the [original] sale would be concealed for fear of exposing the news that it was considered ‘inconsistent with her future status."
It comes after the announcement of a blue plaque for the outside of the Earl's Court flat which Diana lived in with friends before she was engaged.
Diana was bought the flat, in Coleherne Court, by her mother, Frances Shand Kydd, and once said she spent the happiest years of her life there.
Watch: Princess Diana honoured with blue plaque outside former flat