Sheeran announced the album on 23 May 2019.The album is a follow-up to the last of his five EPs No.5 collaborations project (2011).In a post on Instagram, he said, “Before I was signed in 2011, I made an EP called No.5 Collaborations Project. Since then, I’ve always wanted to do another, so I started No.6 on my laptop when I was on tour last year. I’m a huge fan of all the artists I’ve collaborated with and it’s been a lot of fun to make.”
The album is his fourth studio album,although Sheeran has described it as a compilation album. Sheeran released the album’s track list on 23 May 2019, but the names of all the featured artists on the unreleased tracks were redacted.The track list detailed 15 tracks, a departure from his previous three studio albums, which each consisted of 12 tracks.The track list including all guest appearances was revealed on 18 June 2019.