In the perfect follow-up to Kelly Clarkson's emotional appearance on American Idol last week, Demi Lovato arrived to shut the talent competition show down on Thursday night. The pop star basically lit the stage on fire with a powerful performance of not one, but two hits. First, Lovato got the crowd amped up with an exciting rendition of "Confident," and then ended with one seriously breathtaking version of her latest ballad, "Stone Cold." Sometimes it's easy to forget that under all of that bravado, Lovato is one seriously talented singer. Watch her incredible show above, and then check out the moment she absolutely slayed the Lionel Richie tribute at the Grammys in February.