The winning Lotto numbers were 19, 38, 20, 02, 14, 29 and the bonus number was 27.
Set of balls five and draw machine Lancelot were used, Camelot said.
The top prize winner will take home £21,054,380 after matching all six numbers.
A spokeswoman for the National Lottery said: "Tonight's £21,054,380 Lotto jackpot win is the fifth biggest prize to be won on the game so far by a single ticket-holder."
One person matched five numbers plus the bonus ball to win £55,473, while 74 people matched five numbers to win £789 each.
A total of 5,749 matched four numbers, winning £65, while 111,100 people matched three numbers to take home £25 each.
No-one won the top prize of £350,000 in the Lotto HotPicks draw.
The winning Thunderball numbers were 39, 10, 27, 20, 07 and the Thunderball number was 03.
No-one won the £500,000 jackpot.
Saturday's estimated Lottery jackpot is £3.8 million.