Rihanna’s ANTI World Tour features plenty of surprises, including Drake showing up at her Miami concert, but at her Cincinnati stop, the pop singer had the biggest surprise yet. And it was caught on video.

During her rendition of the acoustic ballad “FourFiveSeconds,” RiRi asked a male fan to help her sing a couple of verses from the song. When she extends the microphone to him, the guy delivers an incredible vocal performance that stuns the R&B singer. A 15-second video of the impromptu moment has since gone viral and Rihanna's stunned face is now a .Gif worthy meme.

Cincinnati.com caught up with the guy who showed Rihanna that "Work." His name is Terah Stewart, an administrator at Ohio State University, and a loyal member of RiRi's Navy (aka her fan club).

His surprising performance at her show made for a night he’ll never forget. He tweeted:

Stewart's 15-seconds of fame is far from over. He's garnered thousands of new followers on his social media accounts and there's a slight chance this amateur singer could show off his vocal chops on Ellen.

Watch Rihanna's priceless stunned face at a fan's impressive vocal abilities below.

Worst to Best: Every Rihanna Album Ranked