Mariah Carey treated us to a totally live performance of her holiday smash 'All I Want for Christmas Is You' at the Rockefeller Center Tree Lighting last night. While she looked her festive best and totally belted out the middle-range notes with ease, she seemed to falter a bit on those high notes. To get the full effect of her voice during the performance, Deadspin put together a video isolating her vocals, which you can check out above.

The vid proves that Mimi can totally kick it throughout most of the song -- it's just the high notes that she struggles to hit. And yes, those parts are a bit difficult to watch, considering that Mariah Carey is known for her insane range and her God-given ability to sing notes that only dogs can hear. And sadly for Mariah and her fans, this is not the first time that the pop star has dealt with vocal problems -- she performed off-key while on tour and suffered an embarrassing moment when her voice cracked during her rendition of 'All I Want for Christmas' last year.

While we're not sure what is going on with Mariah's vocals, we hope they get back into tip-top shape ASAP. That being said, we're super grateful she can still belt out the majority of the tune -- and she performed it live!

Check out her isolated vocals in the video above, and watch the full version of her performance in the video below.

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