Mertis John Jr. was Little Willie John’s older brother and is credited as co-writer of the song alongside him. MusicBrainz lists both men as composer and lyricist of the work, and Wikidata carries the same pair of writing credits. Credits on individual pressings and compilations have not always been consistent, with some issues naming only one of the brothers. Accounts differ over how the writing split — the original King label credited only Willie John, while a 2001 biography of his brother says Mertis wrote much of it in Korea and brought it to Willie to finish, with Willie’s name restored as co-writer in 2008; BMI now credits both men.