As Rihanna put it in her tweet below, she was the first person to watch a concert by the Throne, aka Jay-Z and Kanye West, and join them onstage. It all went down last night at London's O2 Arena. She helped the dynamic duo perform two cuts, My Beautiful Dark Twisted Fantasy's "All of the Lights" and The Blueprint III's "Run This Town," and luckily a fan got some decent footage for the rest of us to see. Watch "All of the Lights" above and "Run This Town" below.

[via HipHop-N-More]