Lottery punters are hoping for a share of combined jackpots nearing £100 million over the next two days.
The EuroMillions draw offers an estimated jackpot of £80 million.
If no-one matches the five main numbers and two lucky stars to win the 100 million euro prize, it will roll to the next draw on Tuesday.
On Saturday, Lotto has its first quadruple rollover jackpot of an estimated £19.6 million.
No one has matched all six numbers since September 12.
In a quadruple rollover, the jackpot must be won, so if no one matches all six main numbers then the jackpot amount will be shared between any winners in the next prize level, potentially creating several millionaires.
A National Lottery spokesman said: "What a fantastic end to the month. Friday could see another huge EuroMillions winner created on home soil and Saturday will definitely be a winner, with a Lotto jackpot that has to be won. With the two jackpots combined, that's almost £100 million reasons to celebrate!"