"Billy Stewart" (March 24, 1937 – January 17, 1970) was an American musical artist, with a highly distinctive scat-singing style, who enjoyed popularity in the early 1960s.
Billy Stewart began singing publicly with his mother's group, the Stewart Gospel Singers, as a teenager. He made the transition to secular music by filling in occasionally for the Rainbows, a D.C. area vocal group led by future soul star Don Covay. It was also through the Rainbows that Stewart met another aspiring singer, a very young Marvin Gaye. Seminal rock and roller Bo Diddley has been credited with discovering Stewart playing piano in Washington, D.C. in 1956 and inviting him to be one of his backup musicians. This led to a recording contract with Bo Diddley's label, Chess Records, and Bo Diddley played guitar on Stewart's 1956 recording of "Billy's Blues". Stewart then moved to Okeh Records and recorded "Billy's Heartache" backed by the Marquees, another D.C. area group which was now featuring Marvin Gaye.