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A few days before the scene on the Royal Starship that introduces R2-D2 was to be shot, George Lucas decided that he wanted to have a "barrel" domed droid (an R5 unit) added to the group, which was originally made up out of units with a dome similar to R2-D2. Years earlier, Lucasfilm had given away all the original R3, R4, and R5 domes to Disneyland for their Star Tours (1987) ride, and being on-location at Leavesden studios in England, Don Bies only had a single image to work with, as he quickly made an R5 dome over the weekend. Because of the rush job, it turned out looking slightly different from the original prop, but this same dome was repainted and used for every other R5 unit seen in all three Star War prequels.
Ewan McGregor recalled that his performance in the film consisted of "walking into rooms and looking up".
Keira Knightley's parents tried to convince her not to audition, but the twelve-year-old actress still sought a role, given she was a Star Wars fan.
During filming, Ewan McGregor made lightsaber noises as he dueled. George Lucas explained many times that the sound effects would be added in by the special effects people later on. Ewan said "I kept getting carried away."
Sets were built only as high as the tops of the actors' heads, and computer graphics filled in the rest. Liam Neeson was so tall that he cost the set crew an extra $150,000 in construction.
Warwick Davis: Davis, who played Wicket in Star Wars: Episode VI - Return of the Jedi (1983), is sitting next to Watto during the pod race scene. He also plays Anakin's friend Wald, a Rodian child.
Nathan Hamill: Mark Hamill's son portrays a law clerk in Naboo identified as Rehtul Minnau. He would later appear in Star Wars: Episode VIII - The Last Jedi (2017) as a Resistance member named Saile Minnau, implying that he is a descendant of his previous character.
Rick McCallum: The producer appears on the right, in a floppy wide-brim hat, when Queen Amidala meets Senator Palpatine.
John Knoll: The visual effects supervisor at Industrial Light & Magic plays the Naboo pilot who gets killed during the space battle with the Trade Federation. It happens after Ric Olié says "The deflector shield is too strong."
George Lucas: [1138] The Droid smashed by Jar Jar Binks during the battle has serial number 1138 on his back. THX 1138 (1971) was Lucas's first film and starred Robert Duvall.