Rising to fame in her early 30s, Flack had become an overnight success after Clint Eastwood chose her song, The First Time I Ever Saw Your Face, as the soundtrack for the explicit love scenes of his 1971 movie Play Misty For Me.
The American singer was best known for her hit songs Killing Me Softly With His Song and The First Time I Ever Saw Your Face.
The following year she took the coveted record of the year prize at the Grammys for a second time with Killing Me Softly, becoming the first artist ever to do so.
McCann later wrote of Flack: "Her voice touched, tapped, trapped, and kicked every emotion I've ever known.".
In 2022, Flack announced she was suffering from ALS, commonly known as Lou Gehrig's disease, and could no longer sing.
