Boyfriend

The harmonic structure of Boyfriend draws heavily from early 2000s R&B and the production style of Mike Posner and Pharrell Williams. Rather than utilizing functional diatonic movements aimed at a cadence, the song uses a circular minor-mode loop. The choice of Bb minor provides a dark, moody atmosphere. The inclusion of major 7th and minor 9th extensions adds a 'sophisticated' jazz-pop texture that distinguishes the track from Bieber's earlier bubblegum pop material. The absence of a leading tone (A natural) in favor of the bVII (Ab) ensures the progression remains smooth and avoids the tension-release cycles typical of classical harmony.

Written by Justin Bieber, Mike Posner, Mason D. Levy, and Matthew Musto, the song was designed as a musical departure for Bieber. Mike Posner stated he sought to work with a vocalist who could move the 'matrix' of pop music rather than following existing trends. Mason D. Levy described the result as a more developed, 'edgier' sound compared to Bieber's previous releases.

Released on Bieber's 18th birthday as the lead single for Believe, the track moved away from bubblegum pop toward a style influenced by Pharrell Williams. It debuted at number two on the Billboard Hot 100 and broke the 24-hour VEVO record with eight million views.