Kelly Clarkson and Ariana Grande Talk Performing 'Santa, Can't You Hear Me' For the First Time

The pair pulled off an incredible last-minute performance on Kelly Clarkson's 'When Christmas Comes Around' special on Wednesday night.

Kelly Clarkson and Ariana Grande are two of the biggest stars in pop music, but even they pulled off an incredible feat for Kelly's When Christmas Comes Around special -- performing their new holiday duet, "Santa, Can't You Hear Me," for the first time together, on camera, with no rehearsals!

"It literally was the first time that we had been in the same room singing it," Kelly shared, as the pair sat down for an interview ahead of the special, which airs Wednesday at 10 p.m. PT/ET on NBC. "And it's a pretty detailed song!"

"Oh, it's a vocal," Ariana agreed. "We switch harmonies almost every verse, or every pre-chorus, we flip-flop what we're singing. It was really fun."

"Thank god we did it, but we were definitely out of body, hovering," she added.

"We're professional," Kelly boasted, as the pair shared a high five.

The song, off of Kelly's new holiday album, also titled When Christmas Comes Around, was originally written as a solo track, and Kelly revealed that she almost scrapped it entirely before she got the inspiration to sing with Ariana -- after the two performed together on The Voice season 21 premiere.

"We all did this group performance, and I was like, 'Oh my god, I should make it a duet!' 'Cause I loved how we sounded together," she recalled. "I asked her and she said yes, but it was last-minute and we're all very busy, so we never rehearsed, ever."

The pair obviously pulled it off flawlessly, and clearly couldn't be bigger fans of one another, taking a moment to rave about their When Christmas Comes Around ensembles.

"I'm not really into fashion until it's like, Old Hollywood," Kelly said of her glamorous throwback look.

"She kills Old Hollywood glam," Ari raved, as the pair reminisced. "I had like, a faux fur [muff]... I wanted to throw it, but then I was like, there's no moment."

"I think there's always time to throw a faux!" Kelly replied with a laugh.

Kelly Clarkson Presents: When Christmas Comes Around airs Wednesday, Dec. 1 at 10 p.m. PT/ET on NBC. See more from the dynamic duo in the video below!