Vladimir Horowitz and Art Tatum - Strange Bedfellows!
The reason for this incarnation is Horowitz's fascination of the pianism of Art Tatum. Horowitz, it seems, was mesmerized by Tatum's fantastic arrangement of "Tea for Two", and, it seems, was working out a bit of this tune from time to time on his piano at home.
See if you can find Tatum's "Tea for Two". It was recorded in California just a few years before Tatum died. The incredible schematic that Tatum developed in this arrangement obviously captivated Horowitz, and you have the result in this little outburst in the Horowitz video.
How engrossing it is to realize the open admiration that the titan Horowitz had for Art Tatum.