Most of Joe Johnston’s work on “Star Wars” was done behind the scenes, but in the same way that he cobbled the AT-ST together from model kit scraps, the movies themselves were often a makeshift affair where a lot of pioneering was done. While the AT-ST came together late in the game and “Star Wars” creator George Lucas decided to save it for the sequel (then called “Revenge of the Jedi,” though it would be softened to “Return of the Jedi”), stop-motion animator Phil Tippet had an idea for how they could get some of Johnston’s work into the actual movie. Explaining how that stray shot of the AT-ST in “The Empire Strikes Back” originated, Johnston said:
“Phil Tippett came in and said, ‘What if I took the model?’ The three-dimensional prototype, which was just a static model. All it did was just sort of stand there. He said, ‘What if I took the model, took it apart, and attached the pieces to a stop motion armature? We can build an armature super-fast because it was just basically these aluminum arms.’ He said, ‘I think we’ll have time to get it into a few shots.’ So he did that. He basically destroyed the model but then reattached all the pieces to this armature. He was able to get it into one shot in the background, where it’s just sort of cruising through.”
Johnston also helped design Yoda, Boba Fett, and the AT-ATs (per Yahoo), so he still saw plenty of his work onscreen in “The Empire Strikes Back.” And in the same way that the AT-ST model cameoed in that film, the AT-AT would later make a short appearance in “Return of the Jedi” when Luke Skywalker turns himself into Darth Vader on the forest moon of Endor.