Billy Stewart was a Washington DC musical talent who backed Bo Diddley in the 1950s during Diddley’s Chess years. Stewart would get the chance to make his own recordings on Chess in the early 1960s when the label hired a new A&R person, Roquel Davis.
Rick Simmons in Carolina Beach Music: The Classic Years writes this about Stewart’s first 45 from 1962:
“His first recording was ‘Reap What You Sow” which went to #18 on the R&B charts and #79 on the Billboard Hot 100 … Perhaps more importantly the flip side of the record was a song [Roquel] Davis had asked Stewart to write and record based on his nickname ‘Fat Boy.’ Though ‘Fat Boy’ did not chart, it got a fair amount of airplay and would become Stewart’s signature song”:
“Fat Boy” Billy Stewart 1962
Incredibly, there’s another version of “Fat Boy” without this infectious organ track???
Wikipedia informs us that “Stewart was 12 years old when he began singing with his younger brothers Johnny, James, and Frank as The 4 Stewart Brothers, and later went on to get their own radio show every Sunday for five years at WUST-AM Radio Music Hall in Washington, DC.” WUST is the present-day venerated music venue, 9:30 Club. In the 1940s, this same building – incredibly enough – was a music club named for its co-owner, Duke Ellington (click on link to Washington Post piece).