Demi Lovato's performance of "Cool For the Summer" [1] at the 2015 MTV Video Music Awards was superhot — and Selena Gomez [2] and Taylor Swift [3] agree. While Demi was singing at the Pepsi Stage in downtown LA, a camera caught Taylor and Selena's reactions to her sexy dance moves and surprise guest appearance by Iggy Azalea. The Microsoft Theater, where the main VMAs stage was located, was a little dark, but you can clearly see Taylor's jaw drop when Demi begins her set wearing a skin-baring leotard, while Selena claps excitedly through the whole thing. Watch the video above, then check out Selena's run-in with Nick Jonas [4] and her best moments with Taylor [5].