The lucky winning Lotto ticket for last Saturday's €10.2m jackpot was bought in Spar on O'Connell Street in Dublin.
The busy city centre store sold the ticket for the biggest jackpot win in almost two years.
The National Lottery confirmed this afternoon that the holder of the winning ticket has been in contact.
A National Lottery spokesperson said: “We can confirm that the holder of the €10.2 million Lotto winning ticket was in touch early today and has lodged their ticket with us for safe keeping.
"The ticket holder is going to spend the coming days getting independent legal and financial advice, and will make their prize claim in due course.“
Meanwhile, the owner of the winning Spar store said he was absolutely delighted to have sold such a big winning ticket.
Barry Thompson said he could not believe it when the National Lottery informed him this morning that his shop had sold the golden ticket.
“I had heard on the news that there had been a €10.2 million Lotto winner from Saturday but had no idea it had been sold in my store.
There is a great buzz here in the shop. I employ around 15 staff and the sense of excitement here today is unreal.
“I originally worked in the shop as a manager but took it over in 2008 and this is the biggest ever National Lottery win we have had.
"I am delighted for whoever the winner is, and wish them all the best with their new found fortune," he said.
The store will receive €15,000 for selling the winning ticket.
Mr Thompson said the busy city centre store has a mix of customers with regulars from nearby businesses and a lot of passing traffic and tourists.
He told The Ray D'Arcy Show on RTÉ Radio 1 that it could be anybody who has won as with their location they have a lot of footfall, yet he believes the winner is Irish.
"There's great excitement, I feel like I won it," he said.
The Lotto jackpot win comes the same week a large family syndicate from North Dublin scooped a massive €175m on the EuroMillions game.