Carrie Underwood is geeking out over the New Kids on the Block!

She too turned into a teenage again after performing a special song with them!

The country star had a total fangirl moment after singing “Happy Birthday” to NKOTB members Jordan Knight and Danny Wood during the group’s Total Package Tour stop in Nashville, Tennessee, on Wednesday.

The clearly surreal stage experience left Underwood in shock.

“Um…did I just sing happy birthday to @dannywood and @jordanknight on stage with the NEW KIDS ON THE BLOCK?!?! Yup!” she excitedly tweeted.