I didn't know who the group Ink Spot was until Fred bust out singing their most famous song, the 1939 single "If I Didn't Care" through out the run of Sanford and Son.

A very catchy song that has become the 8th-best-selling single of all time, and Fred Sanford's signature song. I bet Fred singing that song helped with resale of that single through out the 70's.

https://www.youtube.com/watch?v=AMaGs9ievVw