Killswitch Engage brought Jem Siow of Speed onstage in Sydney on 6 November for My Last Serenade.
The song is from Alive or Just Breathing, the band's second album, out in 2002, and it has stayed in the set ever since. Siow took guest vocals on it. Footage filmed by people in the room has been online since the night itself.
Speed are from Sydney and came up through the Australian hardcore circuit, which makes the pairing an easy one locally: the hall already knew who was walking out. Neither band has announced anything recorded together, and nothing suggests this was more than one night.
Killswitch Engage are touring Australia with Sylosis. Melbourne follows on 9 and 10 November, then Adelaide on 12 November and Fremantle on 14 November, with Honolulu on 17 November after that.
The band have been running Alive or Just Breathing songs alongside the newer set all tour, and My Last Serenade is the one that never leaves. Jesse Leach sang it first, left, came back in 2012 and has been singing it since, which means the song has now outlasted two separate eras of the band that made it.