Garrett worked as a vocalist, usually a session singer, with Quincy Jones and Michael Jackson. She co-wrote "Man in the Mirror" for Jackson's Bad and sang a duet with him on "I Can't Stop Loving You." She also sang with Al Jarreau, Johnny Mathis, Debbie Harry, and Madonna, and was heard in Little Shop of Horrors as part of the plant chorus on "Mean Green Mother from Outer Space." Garrett has received two Oscar nominations for Best Original Song, for "Love You I Do" from Dreamgirls (2006) and for "Real in Rio" from Rio (2012; lost to "Man or Muppet").