The Christmas number one is decided by a combination of downloads, sales and streams.
Wham’s festive classic beat songs by Ariana Grande, Gracie Abrams and Mariah Carey to top the chart.
The Official Charts Company said the song had been streamed 12.6 million times in the week leading up to Christmas.
First released in 1984, Last Christmas was originally held off the top spot by Band Aid’s charity single Do They Know It’s Christmas?
Last year, 39 years after it was released, it finally reached Christmas number one.
Wham member Andrew Ridgeley thanked all those who had listened to, downloaded and purchased the song.
He said that the song had “become such a classic, almost as much a part of Christmas as mince pies, turkey and pigs in blankets.”
US pop star Gracie Abrams came in at number two in the Christmas charts with her latest song ‘That’s So True’.
And Mariah Carey’s festive hit ‘All I Want For Christmas Is You’ took the third spot.