The backing male voice is Johnny Bristol.(Motown writer/producer).it was recorded as a mistake.. but Berry Gordy loved the version so much he released it..I agree it does make the song. It was the last song Ms.Ross released with the Supremes..even though it isnt the Mary Wilson or Cindy Birdsong on the backing vocals. It is my favorite Diana and the Supremes song as it was added to their farewell album together. You might remember in 1983 in the tribute to Motown special Diana and Mary refused to stand near each other when they did this song.