Crazy Horse
From The Elvis Costello Wiki
Elvis Costello performed two songs with Neil Young and his longtime backing band Crazy Horse at the 1990-10-26 Bridge School Benefit concert. Down By The River (sung by Young with Costello on background vocals) from this concert appears on The Bridge School Collection, Vol. 2.
Costello also served as opening act for Neil Young & Crazy Horse 2003-09-20 in Irvine, CA.