The National Lottery will be using mobile advertising and posters on Thursday to try to find the winner from the November 2 draw.
The effort comes ahead of the 5pm deadline on Sunday, December 2, for any player who believes they picked the winning numbers, but no longer has the ticket, to write to operator Camelot to register a claim.
Camelot has the discretion to pay prizes for stolen, lost or destroyed National Lottery tickets only if the player has submitted a claim in writing within 30 days of the draw.
If the player can provide sufficient evidence, Camelot will investigate and consider the claim.
After this Sunday the winner must be in possession of their ticket to claim the prize. The deadline for this is May 1.
The owner of the winning ticket matched five main numbers and two Lucky Star numbers to win the entire £76.3 million jackpot.
The winning numbers were 5, 15, 17, 37 and 44 and the Lucky Star numbers were 7 and 11.
Lottery players are being urged to “triple-check” their tickets in case they have won the huge sum.