'If This World Were Mine' (1967) is a swooning duet by Marvin Gaye and Tammi Terrell. The lovers' entwined vocals and gentle rhythms turn its lyrics about perfecting life together into a tender ballad. While never a Top 10 hit (it peaked lower on the charts), it became a fan favorite and a showcase for their natural chemistry (fans often thought they were married!). In later years the song continued to shine: Luther Vandross, for example, scored an R&B #1 in 1990 with his cover version (dueting with Cheryl Lynn). This longevity underlines the song's enduring romantic appeal.