Started out with just a hook for a chorus: "You're Baby's Gettin Gone- She's-a Movin' Uptown". Just kind of grew from there. First song I actually entered in some songwriting competitions (though unsuccessfully). Ironically, I just thought up the name of the dog to use and came up with "Rex". It was a few years later that we were given a Black Lab/Shepherd cross who happened to have the name (you guessed it) "Rex". So... not planned, but worked out well in the end.