Townsend had just overcome a crippling addiction and Let's Get It On was orginally a more uplifting song about get on living life
A friend of Townsend's 16 year old daughter was in the studio, and 33 year old Marvin was immediately smitten and basically freestyled the version we know on the spot
The teen was Jan who Gaye would soon have an affair with and marry, she recently passed away