Dierks Bentley pairs up with country singer Maren Morris on this song. However the track wasn't originally intended to be a duet. "We first recorded it just me, but the song looks at a relationship from a different angle, where the girl is instigating the deceit. So, I felt like it needed a female voice, and I started to hear it more as a duet," Bentley told Rolling Stone. "I love the perspective Maren adds; there's weight to her voice."
The Black album follows a storyline covering the ups and downs of a relationship. "'I'll Be The Moon' is a pivotal part of the flow of this record and is where the storyline of the couple in this series begins," explained Bentley.