http://en.wikipedia.org/wiki/Barbara_Randolph

She was an actress (best known for a bit part as the assistant maid in "Guest Who's Coming to Dinner?") and a singer. She spent most of her career as a fill-in or replacement for other artists in group acts: she replaced Zola Taylor in The Platters, and was signed to Motown to replace Diana Ross in The Supremes in 1966.

When Berry Gordy decided to keep Ross in the group a while longer (she was finally pulled out in 1969), the plan then shifted to possibly hiring Randolph to replace Flo Ballard. Ross didn't like Randolph, so they snatched Cindy Birdsong from Patti LaBelle & the Blue-Belles instead.

Now technically without a purpose for being singed to Motown (a solo female singer on Motown in that era was more or less ignored as far as development and getting good records went in favor of Diana Ross - Martha Reeves and Gladys Knight will tell you that), Randolph briefly subbed for Tammi Terrell on the road with Marvin Gaye after Terrell fell ill. She recorded a few sides for Motown's Soul label (both A-sides were covers of stock H-D-H tunes: "I Got a Feeling" and "Can I Get a Witness") and faded into obscurity. This is her version of "I Got a Feeling", which I prefer to the Four Tops' hit version:

http://www.youtube.com/watch?v=RV_cs-T2Y-Q&feature=topics

More random trivia: her adoptive mother is Lillian Randolph, a radio/film actress from the 1940s probably best infamously remembered today as the voice of the black maid in the "Tom & Jerry " cartoons.