The song initially came about after Bunetta, Ryan and Scott were chatting about their love lives. However, it eventually came to focus on not just romantic love but also as an ode to 1D's fans. "We had this idea of, like, the references in the lyric [are about opposites]," Bunetta explained to MTV News. "When you sing 'silence and sound,' those are opposites. And 'day and night,' 'up and down'," he explained. "And we were thinking, 'OK, were they ever one thing? Before they were day and night, separate things, were they ever one relationship that wasn't [separate].' So you and I, we don't want to be separated [like that].