Usher brought out many big-name artists during his halftime performance over the weekend - notably Alicia Keys. If you thought you heard Miss Keys a little off-key, no you didn't. At least that's what the official records reflect. In a Youtube video (below) Alicia Keys is completely on key during her entire performance. However, if you were watching live then you know there was a slight mishap, but she more than made up for it during the rest of her performance with RnB star, Usher.