As the four remaining contestants took to the stage, they each had to sing a Christmas song as well as a track of their choosing.
Digital Spy rounds up the best Twitter reactions to The X Factor's semi-final below:
1. Fleur East sang Mariah Carey's 'All I Want For Christmas' and then Mark Ronson & Bruno Mars's 'Uptown Funk'
Sorry, but Simon really does pronounce her name like it's a fabric conditioner: "Flureaze". #xfactor
— Scott (@Scott_Ruminates) December 6, 2014
Danced the whole way through that ! #XFactor #XFactorSemiFinal @TheXFactor
— Taemar (@tae_lancaster) December 6, 2014
Even Mariah Carey can't even sing #AllIWantForChristmas like Mariah Carey any more #XFactor
— Ed Roche (@Edroche) December 6, 2014
Is Cheryl even on this planet nowadays? When else is she gonna sing it, Easter? #Xfactor
— Yinka (@VexintheCity) December 6, 2014