Now experts believe "that dress" - as worn by Kate Middleton at a charity fashion show in St Andrews eight years ago - could be worth more than 100,000 when she eventually takes the throne.
For the see-through creation, designed by fashion student Charlotte Todd, is likely to go down in history as an iconic item of royal clothing.
The dress, made of see-through black fabric and through which Miss Middleton's black underwear was clearly visible, was hand-picked by fashion show organisers at the Fife university, where recently engaged Prince William and Miss Middleton were both students. The second in line to the throne was pictured in a 200 front-row seat at the event; it has often been heralded as the moment the prince fell in love with his flatmate.
The designer, who has since given up fashion and now works in an aquarium, said she had already been offered 1,000 for the dress but that she planned to hold on to it. "I don't think I'll sell it - I want it to be in a collection of Kate's royal dresses in future," said Ms Todd, who has kept the dress in a wardrobe at her parents' house since Miss Middleton wore it in 2002.
She added she believed her creation had played a role in the royal romance. "The dress is a part of fashion history - the moment William could first have fallen in love with Kate - and that makes me really proud," she said. "I only made it as a skirt, but they pulled it up on Kate and she wore it as a dress. Maybe if it hadn't have been see-through, William might not have noticed her. I think it has played a part in the royal love story."
The dress was part of a collection designed for Ms Todd's fashion and textiles degree at the University of the West of England in Bristol. "I would love to know what she thought of the dress - she was only 19 at the time and that picture has been used so much over the years," she said. "I always wonder whether she is embarrassed about it, or liked it."
Scottish fashion experts said the dress, which cost Ms Todd just 30 to put together in 2000, had little intrinsic value. "I think the fact the dress has any value at all is only because of its celebrity status," said Scottish Fashion Awards founder Tessa Hartmann. "I think it is definitely more of a piece for an auction house as a piece of history rather than a real fashion statement. I can't really see anyone running out to wear that dress - no offence to the designer, but it's basically just a piece of material."
Kim Eason, head of fashion textiles at Robert Gordon University, Aberdeen, agreed. "It was interesting just because of the body that was inside it," she said. "I hope in the future they'll want to get other garments she's worn, but it's a shame that has to be one of them - it wasn't fashion, it was just a bit of titillation.
"It is like anything with provenance - it becomes valuable. John Lennon's glasses were probably worth $10, but because they're his, they become valuable."
She added: "It is good for the designer that she kept it - I probably would have turned it into dusters."
Christine Satchett, from auctioneer Greasbys, said the dress could be worth a six-figure sum once Miss Middleton became queen. "With important royal items like this, if someone has got the money, they will just keep on bidding," she said.
"I imagine she could get someone to pay 10,000 for it now.
"But in years to come, if Kate was on the throne, it could reach up to 100,000."