The X Factor winner will face challenges from The Wombles, Nirvana and The Only Way Is Essex stars for the Christmas number one, according to bookies.
The yet-to-be-decided victor of the ITV1 talent show is favourite - as in most years - but William Hill has seen a flurry of bets which have cut the odds of challengers considerably.
The firm slashed the price for The Wombles to 7/1 on Monday morning, after earlier giving 50/1 for the furry group's Wombling Merry Christmas single. It is also offering 7/1 for the cast of TOWIE's version of Wham! hit Last Christmas.
But the closest challenger appears to be Nirvana with the band's 20-year-old hit Smells Like Teen Spirit at 5/1.
Fans are being encouraged to buy the track as a response to the usual X Factor domination of the festive chart. In 2009, an anti-X Factor campaign catapulted Rage Against The Machine's Killing In The Name to the top of the charts ahead of show winner Joe McElderry.
Mariah Carey and Justin Bieber's collaboration on All I Want For Christmas Is You is also at 7/1, and another strong tip is Arianna Morgan, a ten-year-old from Essex, who releases her cover of Fleetwood Mac's Songbird next month. She is ranked at 8/1.
However the unnamed song by the X Factor winner is the 1/3 favourite.
Hill's spokesman Rupert Adams said: "The X Factor has had a profound effect on what has traditionally been the country's favourite festive flutter.
"That said, the X Factor winner no longer looks unbeatable, we have seen good money for Nirvana and the cast of The Only Way Is Essex but my money is on Mariah Carey and Justin Bieber at 7/1."
Other contenders include Amy Winehouse (8/1), Westlife (14/1), Adele (14/1), The Smiths (20/1) and One Direction (25/1).