A UK Christmas Number 1 is a big deal, a festive tradition going back decades – ever since the very first one in 1952, when Al Martino claimed the snow-capped summit with Here in my Heart.
Friday 21 December is the date to get in your calendar: that's when the full Christmas Top 40 will be counted down on BBC Radio 1's Official Chart, with Scott Mills from 4pm.
The full, extra festive Top 100 and Official Christmas Number 1 will also be available on OfficialCharts.com from 5:45pm.
Last year, thanks to some starry guest spots from Beyoncé and Andrea Bocelli, Ed Sheeran landed the Official Christmas Number 1 with Perfect. Look back at every Official Christmas Number 1 ever.
As for contenders for this year's festive top spot, current Number 1 by Ariana Grande could hold on with thank u, next. Challengers include rising star Ava Max, X Factor winner Dalton Harris and a charity single by Flakefleet Primary School. Check out the full list of this year's Christmas Number 1 contenders here.
Anyone who wants to be in with a shot at finding the Official Christmas Number 1 Award in their stocking has to make sure their single is available during the week before the cut-off point for sales and streams to be counted toward the chart, which in 2017 is midnight on December 20.