You've probably never heard of the Swiss-German girl duo Boy.

And, judging by their reaction in this video, they didn't expect you to know who they were either.

This video was shot at their first show ever in the U.S. last March at a venue in Brooklyn, N.Y.

While performing its song "Little Numbers," the band was noticeably flustered when the crowd started singing along when they hit the chorus.

If they were surprised by the crowd singing along, they must have been really surprised when people showed up in the first place to see them play!