•
Ayreon -
Universal Migrator Part 1: The Dream Sequencer (2000) • Vocals on "The First Man on Earth" •
Ryo Okumoto -
Coming Through (2002) • Vocals on "Coming Through" and songwriting • Ajalon -
On the Threshold of Eternity (2005) • Co-lead vocals on "On the Threshold of Eternity" •
Roine Stolt -
Wallstreet Voodoo (2005) • Lead & background vocals on "Head Above Water", "Everyone Wants to Rule the World" & "Remember" • Background vocals on "The Observer" & "It's All About Money" •
Hammond organ solo on "Head Above Water" •
Alan Morse - ''Four O'Clock & Hysteria'' (2007) • Keyboards, guitar, songwriting and production •
Dream Theater -
Systematic Chaos (2007) • Spoken voice on "Repentance" •
Jordan Rudess -
The Road Home (2007) • Vocals on "Dance on a Volcano" •
Steve Hackett -
Genesis Revisited II (2012) • Vocals on "The Return of the Giant Hogweed" • Affector -
Harmagedon (2012) • Keyboard solos on "Falling Away & the Rise of the Beast" • Spock's Beard -
Brief Nocturnes and Dreamless Sleep (2013) • Writer of "Afterthoughts" and "Waiting for Me" • Guitar on "Waiting for Me" • Spock's Beard -
The First Twenty Years (2015) • Writer of "Falling for Forever" • Co-lead vocals on "Falling for Forever" • Next to None -
A Light in the Dark (2015) • Mellotron on "A Lonely Walk" • Project Aegis -
And The Rest Is Mystery (2020) • Co-lead vocals • Alan Morse -
So Many Words (2026) • Keyboards and vocals on "I Don't Want to Travel Time if it Takes Forever" • Vocals on "In The Shadow of the Sun" ==References==