Kurtis Blow released "Christmas Rappin'" all the way back in 1979. You don't hear much about Kurtis Blow when chatting about old school rap. Grandmaster Flash, The Sugarhill Gang, and Run-DMC all get far more credit.
Here's Kurtis Blow performing "Christmas Rappin'" on Top of the Pops.
Here's a cool cover of Kurtis Blow's "Christmas Rappin'". It's from CBC's George Stroumboulopoulos Tonight Holiday Special and it features Canadian rappers Kardinal Offishall, Maestro, Moka Only, Michie Mee, Buck 65, Saukrates and D-sisive.