According to The Times, the woman presented the tattered bit of paper to a newsagent.
The woman - who asked to remain anonymous - claims she found the ticket in the pocket of a pair of jeans that had been in the wash.
The winning numbers she claims were on the ticket were: 26, 27, 46, 47, 52, 58 - but unfortunately the wash had scrubbed away the date, as well as the corresponding bar code and serial number.
"You can see 2016 but not the date," she said.
Since the discovery she told The Times: "I've been a nervous wreck."
"I haven't slept all night. Since I found it in my jeans pocket, my daughter and I have been drying it out with the hairdryer."
Camelot confirmed the winning ticket was bought in Worcester.
It has urged the woman to get in touch and send it in within 30 days.
The woman has been in touch with lottery giant and is waiting to see if she is still eligible for the astonishing payout.