Coachella's where the magic happens. Last night, even Taylor Swift got starstruck as Rihanna took to the stage for a surprise performance with Calvin Harris. Belting out "We Found Love" during a crazy-lively set, RiRi left the audience in awe and T. Swift was there to get it all on video. You would think Harris would have let his girlfriend in on the secret, but maybe romance is all about surprises.