William Thomas "Champion Jack" Dupree was an American blues and boogie-woogie pianist and singer. His nickname was derived from his early career as a boxer.

Junker Blues is a piano blues song first recorded in 1940 by Champion Jack Dupree. It formed the basis of several later songs including the 1949 "The Fat Man" by Fats Domino and the 1952 "Lawdy Miss Clawdy" by Lloyd Price. The song is about a drug user's conflict with life and the law, makes references to cocaine, "needles", "reefers", and life in the penitentiary, and contains admonishments against the use of hard drugs.