Superstar Mariah performed her holiday smash hits at the Beacon Theatre on Monday (15 December), and she looked super glamorous for the occasion.
The mum-of-two showed off her curves in the figure-hugging gown, and bared her cleavage thanks to the plunging neckline.
However, Mariah didn't just dazzle in red, as she also slipped into a slinky silver dress to continue her on-stage performance.
Sharing a photo on Twitter, Mariah said: "Finally got into the holiday spirit tonight & it's only the beginning! Loved celebrating with you!"
With Christmas less than 10 days away, we're sure Mariah's festive hit, 'All I Want For Christmas Is You', will climb back up the charts this year.
Last year, the infectious song sold a huge one million sales in the UK since its release in 1994, and it even reached number 12 in the Christmas charts. Can it make a grand festive return this year?!
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Watch Mariah's video for 'All I Want For Christmas Is You' below: