A delivery driver who won $4.8 million in the lottery still worked his Christmas shift to not let his colleagues down

• A supermarket delivery driver won a lottery prize worth nearly $5 million.
• It made him rich enough to quit — but he carried out a December 23 delivery shift all the same.
• His partner said they both intend to keep working to remain grounded.

The morning after a work Christmas party, supermarket delivery driver Jonny Johnston learned he'd won the lottery.

Johnston was in line for £3.8 million, around $4.8 million, from the UK's National Lottery. It was easy enough to quit on the spot.

But Johnston didn't want to let down his colleagues at a Tesco branch in County Fermanagh, Northern Ireland, the Belfast Telegraph reported.

And so he kept up his shift on Saturday December 23 so that somebody else wouldn't have to take it on.

He had been using the same six lottery numbers for 20 years, BBC News reported — and they finally came good in the December 16 draw.

Johnston learned about the win on a night out with colleagues, the Telegraph reported. It said he got an app notification that he'd won, but decided not to check the prize itself, assuming it was something minor like a free ticket for next time.

It was only the next morning, when he checked the app with his partner, Christina Williams, that they realized they'd won a life-changing sum, the Belfast Telegraph reported.

He told the news outlet: "I thought maybe I had won £38,000 but then there were too many zeros. I passed the phone to Christina for her to check and she was in disbelief too. We both began to think that it was a trick, a scam even."

They double-checked with the Camelot Group, the operator of the UK National Lottery, and confirmed the win, later celebrating the prize with coffee, the Belfast Telegraph reported.

Though they were eager to celebrate, Johnston still had another shift to work at Tesco before Christmas.

He told the Belfast Telegraph that he decided to honor his commitment and work it so as not to inconvenience his colleagues.

According to the newspaper, he worked a shift at his local store on December 23, during which he handed over turkeys and other Christmas essentials to customers who had no idea he was now a multimillionaire.

Johnston told the Belfast Telegraph: "I'm still in disbelief. This is a dream come true for me and my family. I've always worked hard, and this win will allow us to do things we could only ever have dreamt of before. "

The couple said they will use the money to provide financial security for their family and possibly go on a Caribbean cruise once Johnston gets a passport, the news outlet said.

Speaking to BBC News, his partner, Williams, said they will both continue to work in some capacity.

"We need to keep our feet on the ground, it doesn't make us different people," she said. "We like to work, it keeps us busy and gives you a purpose."