Sheeran wrote the song with Benny Blanco and Julia Michaels. In an interview with Zane Lowe, Sheeran said that he, Blanco and Michaels started working on the song in Malibu in March 2016 just before he left for a break in Japan. He had the riffs for the song, and first put down five or six riffs, and Michaels then sang 10 or 15 seconds on each. Later, after Sheeran had come back and reviewed the recordings, Michaels returned to flesh out the song with Sheeran and Blanco.