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In trailers and promotional footage, Jyn and Cassian are seen running through the Imperial base and on the beach on the planet Scarif, with Jyn carrying the data storage device holding the Death Star plans. Like many promo shots, such as Jyn standing in an Imperial hallway without her helmet, and a TIE Fighter rising in front of her on a catwalk at the top of the tower on Scarif, these scenes were not used in the final film, where the data storage device was only ever taken to the top of the tower. According to director Gareth Edwards, some shots were cut when the final act of the film was changed and their characters didn't survive at the end. Originally the transmission tower was located away from the base, requiring the Rebels to run along the beach towards it. Because this sequence was taking too long, it was decided to re-shoot it, with the tower now conveniently located in the same building. During an interview with the Director's Guild, Edwards also admitted that at the end of each shooting day, the cast and crew would frequently have fun with the sets and costumes at their disposal. They ended up shooting footage that looked cool, with no intention of ever using it in the finished movie. However, many of these shots looked so great that they ended up in trailers and promo pictures anyway.
Gareth Edwards and his creative team discovered some old film canisters while rummaging around the Lucasfilm warehouses. When he asked what they were, an employee said they were old Star Wars: Episode IV - A New Hope (1977) footage. The discovery led to the inclusion of unused Episode IV material featuring Red Leader and Gold Leader in this movie.
R2-D2 and C-3PO have a brief cameo, making Anthony Daniels the only actor to appear in every movie. (He appears as another character in Solo: A Star Wars Story (2018).)
Diego Luna, who plays Cassian Andor, improvised K-2SO's slap across Cassian's face on Jedha, and Alan Tudyk improvised the line "And there's a fresh one...".
Darth Vader's appearance in this film is meticulously patterned after his look in the original Star Wars: Episode IV - A New Hope (1977). While Vader's chest plate is uncovered in Star Wars: Episode V - The Empire Strikes Back (1980) and Star Wars: Episode VI - Return of the Jedi (1983), his costume initially had his Sith robes draped over his shield, as well as red lenses in the eye holes of the mask. Considering this film takes place mere days before the original film, the costume designers recreated Vader's look down to the last detail.
Anthony Daniels was jokingly disgruntled that Alan Tudyk was allowed to play K-2SO in the relative comfort of a motion-capture suit, whereas Daniels had to endure years of discomfort and injuries in the C-3PO costume. Daniels laughingly cursed at Tudyk after Rogue One's premiere. Tudyk later said that a "Fuck you" from Daniels was one of the highest compliments he had ever received.
Warwick Davis: The Star Wars veteran actor plays Weeteef Cyu-Bee, one of Saw Gerrera's militia members.
Rian Johnson: Star Wars: Episode VIII - The Last Jedi (2017) writer/director plays an imperial trooper controlling the Death Star's superlaser.
Phil Lord, Christopher Miller: as the Death Star crew members manning the super laser shaft. Lord and Miller were set to direct Solo: A Star Wars Story (2018), before being fired due to creative differences.