What happened on the stage? All the Judges are dancing!

<p id="watch-headline-title" class="yt"><span id="eow-title" class="watch-title long-title yt-uix-expander-head" title="Finale: One Direction Performs &quot;Midnight Memories&quot; on The X Factor - THE X FACTOR USA 2013" dir="ltr">Finale: One Direction Performs "Midnight Memories" on The X Factor - THE X FACTOR USA 2013</span></p>