First recorded by Quincy Jones, with Minnie Ripperton, Leon Ware and Al Jarreau (R&B #74 1974).
Hit version by Average White Band (US #39/R&B #25 1975).
From the wiki: “‘If I Ever Lose This Heaven’ was co-written by Quincy Jones (‘It’s My Party‘), Leon Ware, and Bruce Fisher (‘You Are So Beautiful‘) for Quincy’s 1974 album, Body Heat.
“Ware, Minnie Riperton (whose 1975 album, Adventures in Paradise, Ware would produce and collaborate), and Al Jarreau were among the studio vocalists Jones used for the album.