Well, it's an E-type, but technically, not an XK-E. This car, referenced internally at Jaguar as an 'E2A', was first run by Jaguar test driver Norman Dewis on Monday February, 29th 1960. This was an evolution of the Jaguar E1A, built in 1957. The E1A, to my eyes, looks even more like the production E-Type.
Jaguar E1A: