One of four new £5 notes which could be worth up to £50,000 has been found.
Specialist micro-engraver Graham Short engraved a tiny portrait of Jane Austen on the fiver and used it to pay for a sausage and egg sandwich in a cafe in Blackwood, Caerphilly county.
Mr Short's office confirmed the note was found in south Wales, but said its new owner wanted to remain anonymous.
The lucky finder said she intended to give it to her granddaughter as an investment for when she grows up.
This fiver was engraved with: "A large income is the best recipe for happiness I ever heard of", a quote from Mansfield Park, and has the serial number AM32 885553.
Three other £5 notes - spent at a pie shop in Leicestershire and two other shops in Scotland and Northern Ireland - have not yet been discovered.
Mr Short said his work usually sells for about £100,000 and the notes were insured for £50,000 each.
He spent it at the Square Cafe at 14:30 GMT on 8 December and chose the valleys town as it is where his mother was born in 1909.
Mr Short, who is from Birmingham, said: "Generally this artwork is out of the reach for most people. I wanted an ordinary man or woman to find it in their hands.
"I was hoping that the lady wouldn't check it when I gave it to her - which she didn't - because I wanted it to go into somebody's change."