It’s a story often told, how the stiff military boots were too uncomfortable, so instead George Lucas allowed Grand Moff Tarkin himself Peter Cushing to wear comfortable slippers, but it’s far better told by the man himself, so here’s Cushing 46 years ago in 1979 telling his story.
Peter Cushing talks about his experience creating Grand Moff Tarkin for Star Wars A New Hope during this interview in 1979. Peter explains that because his feet were so large, he asked George Lucas to shoot him from the waist up and George agreed and also provided him with a pair of comfy carpet slippers for the rest of shooting.
Grand Moff Tarkin was such a perfect villain for the first film shown to audiences and he perfectly displayed the malice of the Empire.

