Just one day remains in the race for Christmas Number One - and to see whether Justin Bieber's support for rivals the NHS Choir can secure them the top spot.
NHS Choir began trending on Twitter on Wednesday afternoon after the American pop star called on the combined power of his 71.9 million followers to "do the right thing" and help charity single A Bridge Over You win, conceding that "for one week it's OK not to be number one".
By 8pm, Coral bookmakers announced they were suspending betting on who would claim victory as Bieber had all but guaranteed his competitor's triumph.
Representative John Hill said, "It's hard to see the NHS Choir not getting the top spot on Christmas Day now that Justin Bieber, their only rival, is behind their charity song. Before we pulled the plug we saw a huge gamble on the NHS Choir so it is likely to be a popular result with punters."
Bieber's track Love Yourself was narrowly ahead of The Lewisham & Greenwich NHS Choir's single by just 662 combined sales, and his backing could give their campaign the boost it needs to reach the coveted position.
Bieber tweeted: "I'm hearing this UK Christmas race is close ... but the NHS Choir single is for charity. So ...
"So for one week it's OK not to be number one. Let's do the right thing and help them win. It's Christmas. NHS Choir good luck."
He added: "This is what it's all about. Merry Christmas."
Proceeds from the NHS Choir's single will go to charities including Carers UK and Mind.
This is the closest battle for Christmas Number One since 2009, when Rage Against The Machine's single Killing In The Name took on The X Factor winner Joe McElderry's The Climb and won.
Barring a last-minute surge, this year's X Factor winner Louisa Johnson is unlikely to have a look-in for the Christmas Number One as she stalls around seventh place.
Martin Talbot, chief executive of the Official Charts Company, said: "As well as climaxing on Christmas Day for just the fourth time in history, this year's race for the festive number one is looking like one of the closest ever.
"With just two days to go, it really is too close to call - possibly the most exciting battle since Joe McElderry took on Rage Against The Machine in 2009."
Music fans have until midnight on Christmas Eve to download and stream their favoured song, with the result announced by 1pm on Christmas Day.