Margaret Loughrey, who said her £27 million EuroMillions 'destroyed her life', has been found dead at her home in Ireland.
The 56-year-old won the lottery jackpot eight years ago.
Her death is not treated as suspicious after police attended her home in Strabane.
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A Police Service Northern Ireland spokesman said: "Police received a report of the sudden death of a woman at the Ballycolman Lane area of Strabane on Thursday September 2.
"A post-mortem is due to take place but at this stage, the death is not being treated as suspicious."
Northern Ireland Ambulance Service (NIAS) also confirmed they attended the scene.
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A NIAS spokesman said: "We were called to an emergency at 10.30am this morning. No patients were taken from the scene."
Councillor and neighbour Paul Gallagher said the town was shocked after hearing the news.
He told the Belfast Telegraph: "Margaret was well known and did a lot of good, charitable work around the town. People are shocked today."
Ms Loughry was previously unemployed and on benefits before winning a total of £26,863,588 in November 2013.
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By matching five numbers and two lucky stars in the draw, she was able to win the fortune.
At the time, she said in an interview that she had just been to the job centre to fill out an application when she bought the lottery ticket.
She told the BBC: "It's in my name at the minute, it's £27million, it's not going to be mine, it's going to be spread around."
"No point having £27million and being lonely. That can't make me happy, that can only make me happy that everybody else's happy and so far everybody is absolutely delighted."
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Speaking to Sunday Life in 2019, Ms Loughrey said her win had 'sent her to hell and back'.
She said: "Money has brought me nothing but grief. It has destroyed my life.
"I have had six years of this. I don't believe in religion, but if there is a hell, I have been in it.
"It has been that bad. I went down to five-and-a-half stone.
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"I won £27m. I have just over £5m left, but a lot of that I gave to people.
"I will never have peace as long as I live. Even if I didn't have a penny left, I won't."
Featured Image Credit: BBCTopics: No-Article-Matching, Euromillions, Lottery