A claim has been made for the £51.8 million EuroMillions jackpot won by a UK ticket-holder on Tuesday, Camelot said.
The claimant must wait for the ticket to be validated but if successful will scoop the biggest EuroMillions jackpot in Britain this year.
A National Lottery spokesman said: "The National Lottery is making more millionaires than ever. Lotto has made more than 100 since October last year, including its four biggest ever, and now we have the third giant EuroMillions winner of 2016.
"It is great that this big EuroMillions winner has come forward to claim their prize and, of course, the champagne is on ice ready to celebrate their life-changing win.
"Just like every National Lottery game, EuroMillions helps to raise over £34m every week for good causes. This helps fund our athletes competing at Rio, the nation's arts and heritage, and the many thousands of projects in local communities across the UK."
The latest win comes just weeks after a British player was the sole winner of a £24.6 million jackpot.
And in February a ticket-holder in Ireland claimed a 66 million euro (£50 million) share of the EuroMillions jackpot.
But Tuesday's jackpot of £51,818,873 is some way from being the biggest for a UK winner.
Colin and Chris Weir scooped £161,653,000 in July 2011. The cameraman and nurse, from Largs in Ayrshire, reportedly lavished a portion of their winnings on cars for friends, a mansion and a donation to the Scottish independence campaign.