"Part-Time Lover" is a 1985 single by Stevie Wonder, from his album In Square Circle. The song reached number one on the Billboard Hot 100, R&B, dance and adult contemporary charts. The song's simultaneous chart success made him the first artist to score a number-one hit on four different Billboard charts. The song also reached number three on the UK singles chart. The song also featured R&B crooner Luther Vandross humming at the end of Stevie's verses and on backing vocals. Stevie Wonder earned a Grammy Award nomination for Best Male Pop Vocal Performance in 1986, for the song. Wonder is noted in the liner notes of the 4-CD set "Hitsville USA: The Motown Singles Collection Volume 2 1972-1992" as describing the music for the song as an ode to "You Can't Hurry Love" and "My World Is Empty Without You," both by The Supremes, former Motown label mates of Wonder.

Wikipedia