Demi Lovato may be the cutest Christina Aguilera superfan ever.
The 26-year-old, who has kept out of the spotlight for almost a year amid her addiction recovery efforts, was all smiles on Friday night as she cheered, danced, sang along and wept with joy with a group of friends at the Christina Aguilera - The Xperience residency show at the Zappos Theater in Las Vegas.
After the concert, Lovato got to hang out with her idol, who she has worked with before. She posted a selfie of the two backstage.
"The f--king queen herself," Lovato wrote. "A PERFECT, perfect show.. couldn't believe it was opening night because it was so smooth, flawless and sounded incredible. I was entertained the entire time and was so bummed when it was over until I was reunited with this beauty."
Lovato posted on her Instagram Story clips of her and her pals getting pumped for the show on the ride over by lip-synching to "Lady Marmalade" on the stereo, and videos from the concert, including selfie snaps of her fangirling over Aguilera and shots of the fellow pop star onstage.
"Once a fangirl......" she wrote.
"F--KING QUEEEEEENNNN," she added.
Lovato became particularly excited when Aguilera performed "Fighter," singing along passionately.
In 2018, Lovato was featured on Aguilera's single "Fall in Line."
The two performed the song together at the Billboard Music Awards that year.