IN FULL REGALIA : Derek Smalls ( Harry Shearer , left ) , David St. Hubbins ( Michael McKean ) and Nigel Tufnel ( Christopher Guest ) recorded " Back From the Dead " in L.A. IN FULL REGALIA : Derek Smalls ( Harry Shearer , left ) , David St. Hubbins ( Michael McKean ) and Nigel Tufnel ( Christopher Guest ) recorded " Back From the Dead " in L.A. The rock stars in the room have been at this all day .