She's got guts, you gotta give her that! Taylor Swift stepped out on stage sporting a matronly white gown to perform her hit, "I Knew You Were Trouble." Not exactly the super sexy revenge outfit you'd expect when you know you're about to perform in front of your ex, right? Well that was just a tease because halfway through her performance, she stripped out of her dress to a much more risque black satin and lace number. So what did Harry think of the performance? You'll have to watch to find out!