The pop divas performed their duet, "Fall In Line," wowing the crowd with some powerhouse vocals.
Aguilera also opened up about her experience as a coach on 'The Voice,' and explained why she left the show.
Aguilera praised Lovato's 'beautiful work' on Twitter.
The 25-year-old former Disney star has been 'on the other side of the world' in Bali.
The songstress dropped her first new song in years, 'Accelerate,' on Thursday, and opened up to 'Billboard' about her new album and her time on the NBC singing competition.
The pop star also released the first music video for her new song, ‘Accelerate.’
The singer came out as ‘queer’ before retracting her tweets after some fans took offense to the word.
The aspiring musicians were stunned when Lovato crashed what they thought was a television commercial audition in Miami, Florida.
The pop star dropped in on four aspiring musicians to surprise them with studio time and free tickets to her concert in Miami, Florida, courtesy of Lyft.
The 25-year-old singer took to Instagram stories with videos of her stomach, booty and thighs, in an attempt to encourage followers to 'embrace our real selves.'
The pop star also commented on her lack of thigh gap on Instagram Stories.
The group got together to celebrate Hayley Kiyoko's album release on Thursday.
The singer opened up to BBC Radio 1's 'The Breakfast Show' on Thursday about that steamy onstage smooch with her opening act.
The 25-year-old pop star revealed how her opening act surprised her on stage.
