The New Kids on the Block brought their Total Package Tour to Nashville’s Bridgestone Arena last night, with tourmates Paula Abdul and Boyz II Men.

But a tour stop in Music City wouldn’t be complete without a special guest, and that’s just what the capacity crowd got when Carrie Underwood made an appearance to sing “Happy Birthday” to NKOTB members Danny Wood (May 14) and Jordan Knight (May 17).

Watch Carrie’s performance below, and check out a couple of Carrie’s tweets, including one with former American Idol judge Paula Abdul.

Um…did I just sing happy birthday to @dannywood and @jordanknight on stage with the NEW KIDS ON THE BLOCK?!?!

Yup! ❤️💕😎

— Carrie Underwood (@carrieunderwood) May 18, 2017

So happy to reunite with the amazingly talented and equally beautiful @carrieunderwood tonight. So proud of your journey. pic.twitter.com/1ogUI7uTsi

— Paula Abdul (@PaulaAbdul) May 18, 2017