According To Songfacts Norman Whitfield Who Wrote Many Motown Classics Was Commissioned To Write Songs For The Soundtrack Of The Movie Car Wash. He Was Having A Meal Of Kentucky Fried Chicken It Wasn't Called KFC Back Then While Watching A Basketball Game When Inspiration Struck. He Wrote The Lyrics On The Bag Containing The Chicken. The Song Fit Very Well In The Movie Which Was About A Rather Funky Car Wash. For More Info On Car Wash Check Out Http //www.Songfacts.Com/detail.Php?id 5709.