October 1970
Jesus Christ Superstar   
People involved
Annette Brox (vcl); Victor Brox (vcl); Mike d'Abo (vcl); Paul Davis (vcl); Barry Dennen (vcl); Yvonne Elliman (vcl); Ian Gillan (vcl); John Gustafson (vcl); Murray Head (vcl); Neil Hubbard (gtr); Brian Keith (vcl); Henry McCullogh (gtr); Chris Mercer (sxp); Paul Raven (vcl); Peter Robinson (kbr); Bruce Rowland (drm); Alan Spenner (bss); and loads of others.
Apparently Gillan laid down his vocals in 3 hours. I'm unsure as to the accuracy of that, since I've also heard that it took at least a couple of afternoons. Nice anecdote though.

Albums & singles
Jesus Christ Superstar [2lp box] : UK Dec 1970 MCA Records MKPS 2011/2
Jesus Christ Superstar [2lp box] : Germany 1970 MCA Records MAPS 2071/1-2/D
Jesus Christ Superstar [2lp gatefold] : Italy 1970 MCA Records MAPS 2075/6
Jesus Christ Superstar [2cd] : UK 19-- MCA Records MCAD2-10000

Material from above appears on...
Ian Gillan Rock Profile [cd] : UK 1995 Connoisseur VSOP CD 214