U2 surprises NYC subway riders with free concert

New York City is full of surprises! Like when you realize those street performers in the subway aren't just random musicians trying to scrape together some change but are, in fact, U2.

Bono, rocking a blue cowboy hat, and the whole band appeared, unannounced, at a subway stop underneath Grand Central Terminal where they played "Angel of Harlem."

The impromptu performance drew a throng of fans and sightseers who documented the unprecedented mini-concert on their phones and posted pics and clips on social media.

But the band wasn't alone. Joining them -- and dressed in some super casual street performer clothes -- was Tonight Show host Jimmy Fallon.

U2 is taking over Jimmy's show on Friday -- as they will be the night's only booking -- and it looks like this magic metro moment is likely part of a pre-taped segment for the band's special episode.

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The band was originally supposed to appear for a special U2 episode of The Tonight Show in November, but Bono's devastating bike accident -- which required extensive medical treatment and surgery -- postponed those plans.

It should be interesting to see what Jimmy and the boys of U2 have planned for the momentous episode.

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After Bono's painful accident in November, he was unable to perform with the band for several months. At a concert for World AIDS Day in New York, Chris Martin and Bruce Springsteen filled in for Bono, and the band was billed as "U2 Minus 1."

Check out the video below for a look at Martin and Springsteen singing some of the band's most iconic singles.