A 53-year-old Massachusetts mother of two who scooped the largest single jackpot in US history – US$758.7 million – said it was a dream come true on Thursday (Aug 24) and immediately quit her hospital job of 32 years.

Mavis Wanczyk said she had played the lottery as a "pipe dream," never believing that it would one day be possible for her to retire early from the Mercy Medical Center, where she worked in patient care.

On Thursday, that dream came true.

"I've called them and told them I will not be coming back," she said to laughter at a news conference hosted by the Massachusetts State Lottery.

"I'm going to go hide in my bed!" she added when asked how she planned to celebrate, wearing black-framed spectacles, a zip-up hooded black sweater over a grey lace top, necklace and shoulder-length thick auburn hair.

Wanczyk selected the winning numbers – which included family birthdays – and bought the ticket from a convenience store in Chicopee, a small town 160 kilometers west of Boston, calling it "a chance I had to take."

"I was there just to buy it for luck," she explained, chewing gum and grinning. Accompanied to the news conference by her mother and two sisters, she was still dazed after her monumental win. It came nine months after the father of her children, William Wanczyk, a former firefighter, was killed on Nov 6 by a hit-and-run driver while waiting at a bus shelter in the Massachusetts town of Amherst, US media reported.

A local man, accused of driving a pickup truck at high speed, was subsequently charged with offences including motor vehicle homicide, manslaughter while under the influence and leaving the scene.

Powerball called Wednesday's draw "the highest jackpot won on a single ticket and the biggest lottery prize ever awarded to one single person."

The US$758.7 million jackpot is Powerball's highest since a January 2016 world record of US$1.6 billion, which was split between three ticket holders from California, Florida and Tennessee. Each took home US$528.8 million.

The winning numbers were 6, 7, 16, 23 and 26, from five white balls, and 4 as the so-called Powerball number on a red ball.

The retailer that sold the winning ticket is to receive US$50,000, which he has committed to local charities.

Wanczyk now has the choice of taking the jackpot as an annuity spread over 30 years or a one-off cash lump sum - reportedly US$336 million after taxes.

"The first thing I want to do? I just want to sit back and relax. I had a pipe dream and my pipe dream has finally come true," Wanczyk said.

She said she found out she had won from a fireman colleague as they were leaving work at night and promptly went into shock.

"I couldn't drive anywhere, I couldn't do anything," she said. "So he followed me actually to make sure I was safely home. Now it's like, 'I am a winner,' and I'm scared, but I'll be OK."

Wanczyk, who has a 31-year-old daughter and 26-year-old son, said she had been "OK" financially and had yet to work out how to spend her millions, other than paying off the car she bought last year.

She said she now wanted to be alone to "figure out what I want to do."

While she could have remained anonymous, she said she came forward so quickly because she wanted to "get it over," hoping that everybody would leave her alone.

Six other people won US$2 million each and 34 players walked off with US$1 million in Wednesday's draw, Powerball said.

The lottery is played in 44 states, Washington DC, Puerto Rico and the US Virgin Islands. The draw takes place every Wednesday and Saturday nights.

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