Ed Sheeran and Eminem locked in a battle for the Christmas number one

Ed Sheeran's Perfect remains the front-runner for this year's Christmas number one, but Eminem is closing in fast.

The rapper is a surprise new entry at number two in the mid-week chart update with River, a song that dissects a toxic relationship.

According to the Official Charts, Sheeran is still ahead on pure sales, but Eminem is getting more streams.

"You couldn't call it one way or the other without being wrong," charts expert James Masterton told the BBC.

However, River also features guest vocals from a certain Ed Sheeran, the star could essentially replace himself at the top of the chart.

The Official Charts Company will reveal the winner on Friday, 22 December.

Also in the running is Wham!'s Last Christmas, which fans are trying to get to the top spot as a tribute to George Michael, who died on Christmas Day last year.

The 80s classic is at number three in the mid-week charts, but seems unlikely to climb higher, based on current figures.

There are also rumours that Adele could release a last-minute Christmas single. The Sun says it could be a tribute to the victims of the Grenfell Tower fire, while other reports suggest it could be a George Michael cover.

Adele has been a vocal campaigner for the Grenfell victims, attending a vigil at the tower block and asking fans at Wembley to donate to the relief efforts.

However, any new single would have to sells tens of thousands of copies in a short space of time to overtake the current Christmas chart contenders.

Earlier this month, Sheeran seemed to guarantee his grip on the charts by releasing multiple versions of Perfect - including a duet with Beyonce and a classical rendition featuring Andrea Bocelli.

Eminem's challenge comes as something of a surprise: River, a track on the star's ninth album, Revival, was only released on Friday and has not been promoted as a single.

"Ed's multiple versions are counting in his favour," says Masterton, who runs the Chart Watch UK website. "And he had the dynamite position at the weekend - he got to be the featured star on the Strictly final.

"You immediately saw a huge leap in his sales after that. But his record has been out for a good few weeks [and] I don't think anyone quite anticipated there'd be this one Eminem track that's had the impact it has.

"It actually does make if far more interesting."

The chart battle has left bookmakers in an awkward position. After Sheeran released the Beyonce version of Perfect, they started taking bets on him being Christmas number one "either solo or as a duet".

That definition would seem to include the Eminem song, meaning they'll have to pay out whoever emerges victorious.

Follow us on Facebook, on Twitter @BBCNewsEnts, or on Instagram at bbcnewsents. If you have a story suggestion email [email protected].