Last month, an Athlone, Co Westmeath-based solicitor representing the winner said an issue surrounding the ticket had been resolved.
Solicitor Tony McLynn, acting for the winner, said the principal sum plus interest would be paid out.
Mr McLynn said comments made by Premier Lotteries Ireland, the licenced operator of the National Lottery, that the money had not been paid out had fuelled speculation and rumour.
The solicitor said “a matter of clarification” had been settled and all parties were happy to move on.
The National Lottery had earlier said it always worked to ensure due process in its claims procedure and never commented on the specifics of individual claims.
The Lotto jackpot that had been rolling since January 27 was won on March 5.
It is the biggest ever win in Co Sligo. The €20 normal play winning ticket was bought in Matt Lyons’s XL Shop n Stop on Stephen St, which sold a €4.3m jackpot winning ticket in December 2009.