They perform 'Silent Night,' Until a mystery guest in the shadow has all going wild!

<p id="watch-headline-title" class="yt"><span id="eow-title" class="watch-title long-title" title="Kelly Clarkson - Silent Night ft. Trisha Yearwood, Reba McEntire" dir="ltr">Kelly Clarkson - Silent Night ft. Trisha Yearwood, Reba McEntire</span></p>