William P. Homans III, (born 1949) professionally known as “Watermelon Slim”, is an American bluesmusician. He plays both guitar and harmonica. He is currently signed to NorthernBlues Music, based in Toronto, Ontario. Homans has also earned bachelor’s and master’s degrees from University of Oregon and Oklahoma State University.

Homans was born in Boston, Massachusetts, United States, but has said that he was raised in North Carolina, where he was first exposed to blues music from about the time he was five years old. During childhood, he sang in choirs and glee clubs. Homans later explained that he first played music in 1958, on a set of bongo drums. A year later, he acquired a harmonica. It took almost a decade before he became sufficiently experienced to take on a professional gig at Middlebury College in Vermont.