Earl Van Dyke was at the very heart of Motown: the Detroit born keyboard player and bandleader was the founder of The Funk Brothers - the label's house band; without them there wouldn't have been a Motown. It's as simple as that. Anyone who's seen Standing in the Shadows of Motown will, I'm sure, concur.
From time to time Van Dyke would slip anchor - they'd allow him to open for the names over the door. That's when he'd get to play tunes like this: it's a sure fire floor-filler that goes by the name of 6 X 6.