*Rick Price – bass guitar (1970) The Electric Light Orchestra/No Answer
*Carl Wayne – vocals (1972) ELO 2 The Lost Planet
*Marc Bolan – guitar (1973) On the Third Day
* Ellie Greenwich – backing vocals (1975) Face the Music
* Susan Collins – backing vocals (1975) Face the Music
* Nancy O’Neill – backing vocals (1975) Face the Music
* Margaret Raymond – backing vocals (1975) Face the Music
* Mary Thomas – Operatic vocals (1976) A New World Record
* Patti Quatro – uncredited backing vocals (1976) A New World Record
*Olivia Newton-John – vocals (1980) on Xanadu
*Rainer Pietsch – co-arranger and conductor (1981) Time
*Christian Schneider – saxophone (1986) Balance of Power
*George Harrison – slide guitar, backing vocals (2001) Zoom
*Ringo Starr – drums (2001) Zoom *Suzie Katayama – cello (2001) Zoom
*Roger Lebow – cello (2001) Zoom
*Dave Boruff – saxophone (2001) Zoom
*Laura Lynne – backing vocals (2001) Zoom
*Rosie Vela – backing vocals (2001) Zoom
*Kris Wilkinson – string arrangements (2001) Zoom