The winner, who wished to remain anonymous, held one of four division one winning entries across Australia in Monday and Wednesday's Lotto draw, each taking home a guaranteed $1 million.

The winning ticket was purchased at Jamison Centre News, Macquarie. Owner Graham Donovan was overjoyed when he heard he had a winner.

"I was shocked when I first heard the news. The best part is knowing that one of our customers has become an overnight millionaire," Mr Donovan said.

It's the second time in 10 days a division one win has happened in the ACT.

A group syndicate saw 10 ACT and NSW residents win a total prize of $1.717 million in Saturday Lotto's $20 Million Superdraw.

Remarkably, Jamison Centre News sold a share in that division one winning syndicate.

"It's very interesting, considering it's two in the space of two weeks it's great. We need more of it," he said.

"They say these things come in threes, so hopefully there's another win on its way."

It is unknown what the winner will do with their winnings, but with more than $1 million under their belt, they could line one million $1 coins side-by-side around Canberra's Capital Hill more than eight times.