Jackie and Roy was an American jazz vocal team consisting of husband and wife singer Jackie Cain (1928–2014) and singer/pianist Roy Kral (1921–2002). They sang together for 56 years and made almost 40 albums.Kral's 2002 obituary in The New York Times said: "Their voices had similar ranges but were an octave apart, creating unusual harmonies."

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