The pop group, made up of Ian Axel and Chad Vaccarino, were humbled when they heard that Christina wanted to re-record their Say Something single.
"It was really hard to process," Chad admitted.
But for Christina, the decision appeared to be a no-brainer.
"It's so simple," Christina said of the pop duo's hit, explaining that the track came along at a time where she's been feeling particularly inspired.
"I'm only taking on projects that feel good to me and represent, as always, a purpose of the here and now in my life," the pop diva continued. "That's what this song, Say Something, actually does for me."
Ian described their creative process for the number, saying, "When we wrote the song, we felt so alone. We write to heal ourselves but we also write to connect. It's the human experience. We're all in this thing together."
Fans can watch the song performed Tuesday on The Voice.
Their debut full-length album, Is There Anybody Out There?, is available for pre-order starting November 4.