It's been a minute since we've seen Rihanna performing. Or it had been until last night in L.A. when Kanye West brought her on stage during his set at FYF Fest. West was filling in the Saturday night headlining slot for Frank Ocean, who canceled at the last minute. If Ocean's fans were displeased by his replacement, West was bringing out all the stops to give them a good show — including Rihanna. West plucked RiRi from the crowd, where she was watching the show, to join him on their hit single "Four Five Seconds." She sang from the sidelines, grinning broadly as the pair passed the mic back and forth. West pulled her fully on the stage, even though she was just rocking an oversized hoodie and black lipstick, for a full-on rendition of "All of the Lights." West's wife, Kim Kardashian, was at the show also. She Instagrammed a few cute poses with him as well as a shot with her sisters (minus Kylie, who appears to still be celebrating her birthday somewhere). This is only whetting our appetite for R8, the long-delayed Rihanna album that she's been promising for the last two years. We're so ready RiRi, bring it on!