Arthur and Emma Howard from East Kilbride scooped their share of in the lotto draw last Friday.
The 73-year-old taxi driver has since handed in his notice.
The win was not confirmed until Saturday when he visited his local shop and the winning numbers were verified.
In an interview with the East Kilbride News, son Allan revealed how the news was broken to his mother, Emmma.
He said: “My mum was puzzled when she came home and saw everyone at the windows.
“She had no idea what was going on. My dad took her hand and, through tears, said, ‘Hen, we’re millionaires.’
“It’s without a doubt the happiest time of our lives.
“My mum and dad aren’t drinkers but the champagne came out after that.”
Howard regularly purchased five lottery lines at his local shop every Friday and Saturday.
The couple remain tight-lipped about their plans for the money, except to say that a holiday to Dubai was on the cards.