Camelot says the big prizes should result in a 96% and 23% sales uplift respectively.
The first of the two big draws will be the EuroMillions Super Jackpot draw today (4 February), which has an £107m jackpot. Then on Saturday (5 February), Lotto has an £11.8m draw.
Camelot’s retail director, Jenny Blogg, said: “It’s not that often we have two huge draws 24 hours apart, so Friday and Saturday are going to be extra special for both National Lottery players and retailers.
“Get talking to your customers about the draws to help generate interest and excitement, and make sure your POS is already sited to really help maximise the sales opportunities that these incredible draws bring.”