I think your thinking of the original sound track of the Samuel Goldwin production of Porgy & Bess 1959. The sound track is on a Colombia Masterworks recording #os2016 but is only available used as far as I know. I searched 10 years ago for a cassette recording but could not find it. My only copy is in bad shape but is one of my favorite albums of all time. Artists are Sidney poitier, Dorothy Dandridge-( I think she's dubbed),Sammy Davis, Jr. and Pearl Bailey. Oddly enough, Cab Calloway sings "It ain't necessarily so" on the sound track- Sammy Davis Jr. sang it in the movie but I think there was some kind of royalty dispute or something that kept his recording off the sound track. If you can find this album at a Library used book sale or garage sale, buy it. I searched e-bay but it's not there except for maybe a real to real tape.