John Maurice Hartman (July 3, 1923 – September 15, 1983) was an American jazz singer who specialized in ballads. He sang and recorded with Earl Hines' and Dizzy Gillespie's big bands and with Erroll Garner. Hartman is best remembered for his collaboration in 1963 with saxophonist John Coltrane, John Coltrane and Johnny Hartman, a landmark album for both him and Coltrane.

Source: Wikipedia (https://en.wikipedia.org/wiki/Johnny_Hartman)