Then you're going to LIVE for this video!!!
She's gone undercover -- and she OWNS it!
Ch-ch-check out the video for Birthday here (above)!
Bravo, Jonas Brothers!! Bra-Vo!!
Of course, we're very aware this was Nick Jonas' idea!
As the biggest Broadway lover of them, Nick shined his spotlight bright when he starred in How To Succeed!
And he wanted to continue the New York stage love by covering Once's Falling Slowly with his brothers. Adorable!!
As you know, the boys packed the house at Radio City Music Hall on Thursday. And we can see why!
Ch-ch-check out their haunting rendition of the song (above)!!
And tell us, would U have clapped hard enough for an encore after that performance?