It's a find that could earn a student a mint - a 50 pence piece with next year's date on. Sarah Legg was handed the coin in her change after paying for lunch at her college and noticed an unusual design.
The silver coin features one of 29 designs by members of the public created for the Royal Mint ahead of the 2012 Olympics.
Now the 17-year-old forensic science student hopes to sell it to coin collectors to help pay her university fees after she leaves Fareham College in Hampshire.
However, the Royal Mint today said the coins have slowly been released into circulation since October so people should expect to start finding them in their change now - and their value is only 50 pence.
Emma said: 'I was just getting some food at college and thought the coin looked very shiny, so I took a closer look.
'I thought I had gone into the future with the markings it had. Where the date it is made was it said 2011.
'I was a bit shocked to be honest and showed all my friends. It looks like the Royal Mint have made a blunder.'
Coin experts are perplexed by the find. Rob Davies, of Portsmouth, Hampshire, said: 'It is very unusual and special and the young girl should keep it.
'I could not put a price on how much they cost but it is very special and similar to the 20 pence issue a few months ago.'
Royal Mint spokesman Nick Scargill, said: 'It is unusual but they are perfectly legal tender. It is very special.'
Previously there have only been 16 designs of the 50 pence piece which was created in 1969.