The pop divas performed their duet, "Fall In Line," wowing the crowd with some powerhouse vocals.
Bow down to these two queens!
Sporting a black leather coat, and backed by an army of dancers in military-esque garb, Aguilera kicked off the first verse of the song. Lovato joined on her part, in a matching Matrix-like coat.
The two harmonized powerfully, as they concluded the song kneeling together in near tears, head to head as video of two girls being pulled away from each other played behind them.
Before the performance, the singers teased the duet, demonstrating the closeness they feel performing together.
"Nothing but excitement to share the stage with this legend @xtina #xtinademi_bbmas," Lovato tweeted on Saturday.
Aguilera also shared a black-and-white photo of the pair huddling together on stage in rehearsal for the big moment.
"Unit y= Power," the 37-year-old captioned the image.
The pair of powerhouses collaborated on the track for Aguilera's upcoming album, Liberation, and couldn't help but share their admiration for one another leading up to the song's release..
"I believe our paths were destined to cross and I am so proud to come together from the pasts we’ve overcome," Aguilera wrote on Twitter. "To the strong women we are today! You are truly a GEM, I have immense love and respect for you! You are an inspiration for future young girls of your generation. Beautiful work! #FallInLine @ddlovato ♥️."
The feeling was mutual from the "Sorry" singer.
""BUCKET LIST ITEM 1 ✔️ @xtina featuring me ?? #FALLINLINE http://demilovato.co/fallinline," Lovato added. "I hope you love this song as much as I do. It’s such an honor to lend my voice to this anthem for women with one of the most inspiring individuals I’ve ever met."
Lovato first hinted at her collaboration with Aguilera in an interview with Billboard in February, teasing that while she "can't give away" who the artist was, "it's an incredible song." Aguilera finally confirmed her collab with Lovato in her May interview with Billboard.
"We went through a few names of women. I needed a belty singer, and she took it to the next level," she said. "I almost cried when I first heard her on the record."
See more on Aguilera in the video below.