
After replacing Frank Ocean as the headlining act at the FYF Fest days before it began, the "All Day" rapper not only killed his performance Saturday, but he also surprised the crowd and brought out Rihanna to wrap up his show (making it one epic night).

Still, Rihanna proved she was game for it when she grabbed the mic, hopped up and performed "FourFiveSeconds" with him, and sang her part of "All of the Lights" while she was at it. When the latter happened, people lost it - as you can see in the video below taped by a concert attendee.
In addition to Rihanna, Kim Kardashian, Kourtney Kardashian and Kendall Jenner were also in the audience at the show. Kim made sure to post several shots from the show, including one of herself with her sisters and a friend, captioning it, "Damn they don't make 'em like this anymore."
The Keeping Up With The Kardashians star also posted a shot of herself with her hubby, showing off her pregnant belly while she was at it in a black body-hugging dress.