Few people on Earth love the New Kids on the Block the way Carrie Underwood loves them.

But, the New Kids might love Carrie just as much. During a show inside Carrie's second Nashville home-- Bridgestone Arena, the best boy band of all-time, invited Carrie on stage to sing Happy Birthday to Jordan Knight. She did.

But, then-- they sang to her. She danced, she smiled, she sang along.

Carrie's birthday is March 10, but you know, who cares?

Carrie enjoyed the rest of the show with friends, where she said Jordan, Joey, Danny, Donnie and Jonathan, "still got it."