Originating in vocal jazz, scat singing or scatting is vocal improvisation with wordless vocables, nonsense syllables or without words at all. In scat singing, the singer improvises melodies and rhythms using the voice solely as an instrument rather than a speaking medium. This is different from vocalese, which uses recognizable lyrics that are sung to pre-existing instrumental solos.

Ella Jane Fitzgerald was an American jazz singer, sometimes referred to as the "First Lady of Song", "Queen of Jazz", and "Lady Ella". She was noted for her purity of tone, impeccable diction, phrasing, timing, intonation, and a "horn-like" improvisational ability, particularly in her scat singing.