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 Tähtien sota (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).)
Darth Vader's appearance in this film is meticulously patterned after his look in the original Tähtien sota (1977). While Vader's chest plate is uncovered in Imperiumin vastaisku (1980) and Jedin paluu (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.
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...".
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: 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.