Lionel Richie "Running with the Night"

Richard Marx owes Lionel Richie a beer or two for helping launch his career. Marx provided backup vocals for a handful of Lionel's tunes including "Running with the Night" in 1983. After Marx became a household name (and a staple of Adult Contemporary radio), Lionel appeared as a background vocalist on "The Way She Loves Me".

Paula Abdul - "Rush Rush"

Paula Abdul released "Rush Rush" in 1991 -- her first ballad.  While the song was different from her previous upbeat pop singles, the soft violin-filled "Rush Rush" proved to be a huge success for the future American Idol judge -- the song topped the Hot 100 and Adult Contemporary Charts for five consecutive weeks.  FUN FACT: Paula Abdul was the choreographer for the 1987 movie Can't Buy Me Love starring a very young Patrick Dempsey.