“Eastside” focuses on the relationship of two people who fall in love. It follows them as they go through their relationship and as they reminisce about their memories together.

The song marks the debut of the multi-award winning songwriter, producer and musician Benny Blanco, featuring Khalid and Halsey. Its release was first hinted at by some of his fans on Twitter, just days before its release. Benny Blanco himself then confirmed the song through Twitter on 11 July 2018: