TabScout.

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.