A notable moment emerged at Machine Gun Kelly’s concert in Chicago on December 4, 2025 — during his current tour promoting Lost Americana. Midway through the performance, MGK surprised the audience by bringing out longtime collaborator Halsey for an unannounced duet.

The two launched into a live rendition of their 2020 pop-punk track Forget Me Too — a reunion that reignited excitement among fans. Halsey remained onstage afterward for a performance of “Bad Things,” a song originally featuring a different guest artist, with Halsey stepping in seamlessly for the vocal parts.
Beyond the performance, MGK took a moment to address Halsey’s public health struggles. He praised her resilience — referring to her “fighting every day” through illness, acknowledging the personal difficulties she’s endured while continuing to create music and perform.
The surprise appearance and emotional tribute became one of the defining highlights of the night — a rare full-scale reunion of MGK and Halsey on stage, blending nostalgia, vulnerability, and solidarity in a performance that resonated deeply with the audience.