was rumoured to be gladys knight but who knows ,just brilliant . The backing track was from an album of tracks intended for a film score that Berry Gordy commissioned to be recorded at United Sound Systems in Detroit around 1972/73. Mike Terry arranged them and the Funks with DSO performed them. Who and how the vocal got to added I know not. Apparently Motown (Universal) have got the album in their vaults but, as is normal with them, refuse to release or even disclose its existence. Pity ,this was on youtube .
kev