•
Ayreon: Åkerfeldt sings the parts of "Fear" in
The Human Equation, the 2004 release. •
Candlemass: Åkerfeldt performs vocals for one song on the Candlemass 20-year anniversary DVD. •
Devin Townsend: Åkerfeldt appeared as a guest vocalist for
Deconstruction. He sings on the song "Stand". •
Dream Theater: Åkerfeldt performs a
spoken word part in "
Repentance" on their 2007 album
Systematic Chaos. He also sang the second verse of the same song on its first live performance, during the Progressive Nation 2008 tour. During the same tour, he also performed the growled part of the song "A Nightmare to Remember" with the band live. •
Edge of Sanity: Åkerfeldt provided vocals and guitar parts in Edge of Sanity's 1996 album
Crimson, and also wrote lyrics for a song on
Infernal. •
Ghost:
Prequelle (2018) – acoustic guitar on the instrumental track "Helvetesfönster". • Horrified: Åkerfeldt growls a few words on "Avatar of the Age of Horus" off of their
Deus Diabolus Inversus album. •
Katatonia: Åkerfeldt sings on the 1996 album
Brave Murder Day, and the three-song EP
Sounds of Decay, released 1997. He also performs backing vocals on the album
Discouraged Ones and was the vocal producer on ''
Tonight's Decision''. •
Ihsahn: Åkerfeldt performs on the song "Unhealer" from the 2008 album
angL. •
OSI: Åkerfeldt performs lead vocals on the track "Stockholm" for OSI's 2009 album,
Blood. •
Porcupine Tree: Åkerfeldt sings backing vocals on "Deadwing", "Lazarus", "Shesmovedon" and "Arriving Somewhere But Not Here" and plays a guitar solo on "Arriving Somewhere But Not Here" on the 2005 album
Deadwing. •
Roadrunner United: Åkerfeldt performs vocals on the song "Roads" alongside
Type O Negative keyboardist
Josh Silver on the
Roadrunner Records 25th Anniversary album
Roadrunner United: The All-Star Sessions. •
Soilwork: Åkerfeldt performs vocals on the title track of the album ''
A Predator's Portrait''. •
Steve Hackett:
Genesis Revisited II (2012) – vocals on "Supper's Ready". ==References==