In July 2019, Halsey was spotted in the studio with Bring Me The Horizon members Oliver Sykes and Jordan Fish.

During their time together, the trio teased a then-unreleased track titled “Experiment On Me” for the Birds of Prey soundtrack. In December 2019, Halsey featured in a BMTH track titled “¿” and went on to release “Experiment On Me” as a solo release.

On July 27, Sykes shared a snippet of another unreleased song to his Instagram story. It is believed that this song – given the fan title “Burn” – is the same as a song registered to ASCAP as “Feel This Lonely.” A snippet of the track leaked in December 2020, confirming some more of the lyrics collected here.