It's definitely no secret that Carrie is a HUGE NKOTB fan!
(P.S. I'm obsessed with her outfit and want it in my closet immediately!)
NKOTB performed last night in Nashville and Carrie showed up and even sang a “Happy Birthday” dedication to Jordan Knight!
“We decided to bring Carrie Underwood out to sing Happy Birthday to Jordan,” Donnie Wahlberg says in the video below