2017 Christmas No. 1: Ed Sheeran - 'Perfect'

Greg James will be counting down this year's full Christmas Top 40 on on BBC Radio 1 on Friday 22nd December 2017. The chart will include all singles and download sales up until midnight on December 21st. As always, it's the biggest chart of the year and the list of contenders will continue to grow as we get nearer to the festive season.

It goes without saying that that whoever wins the X Factor is in with a chance of grabbing the top spot, but it's not guaranteed, after all Clean Bandits' 'Rockabye Baby' top the Christmas chart last year. There's also whichever song John Lewis choose to use in their iconic Christmas ad, in previous years songs from their commercials have caused a stir in the charts.

And there's likely to be a whole host of novelty and charity singles, as well as some tributes to dead celebrities. Perhaps Tom Petty or Linkin Park's Chester Bennington?

The series usually comes to an end toward the end of December, just in time for the Christmas single to be released. The current bookies' favourites to win the show are Grace Davies, Holly Tandy, Sean & Conor Price, Rak-Su, and The Cutkelvins.

The songs used are often covers, and are often recorded by unknown, or up and coming artists. Previous years' ads have featured artists including Tom Odell, Gabrielle Aplin, Slow Moving Millie, The Vaults, and Lily Allen.

The advert is usually revealed in the ad break during 'The X Factor', usually on the second or third weekend of November.