|"Once Upon a Time"|
|Single by Marvin Gaye and Mary Wells|
|from the album Together|
|"What's the Matter with You Baby"|
|Genre||Pop, rhythm and blues|
William "Mickey" Stevenson
Written by Clarence Paul, Barney Ales, Dave Hamilton and William "Mickey" Stevenson, the song discussed how the two narrators felt lonely until they met each other referring to their past as it happened "once upon a time".
The song brought simultaneous top forty pop success for the duo as the single hit number nineteen while its b-side, "What's the Matter with You Baby" peaked at number seventeen on the pop singles chart. The song's co-writer, Dave Hamilton, plays the vibraharp solo.