WATCH: Louisa Johnson Sang Mariah Carey's 'All I Want For Christmas Is You' 100% A Cappella, And... WOW.

10 December 2017, 18:40 | Updated: 10 December 2017, 19:50

THE VOCAL CHORDS ON HER! WOW.

There's a reason why Louisa Johnson won 'The X Factor'. It's because she could literally sing the ingredients on a can of spaghetti hoops and it would sound magical.

That's why Rob Howard decided to get her to show off her talent for everyone at #CapitalJBB backstage.

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After she rocked The O2 singing Mariah Carey's classic Christmas anthem on Saturday, Rob asked the 'So Good' gal to perform 'All I Want For Christmas Is You' totally a cappella, and...

WOW.

We wouldn't even judge you if you wanted to listen to this right up until August.

> Louisa Is Going To Be 'So Good' On The #CapitalJBB Stage, So Get Our App And Check It Out...

Wait until you hear Louisa sing some of the biggest songs of the year. She's good, ain't she?