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: Episódio IV - Uma Nova Esperança (1977) footage. The discovery led to the inclusion of unused Episode IV material featuring Red Leader and Gold Leader in this movie.
Alan Tudyk, who plays K-2SO, improvised both the slap across Cassian Andor's face on Jedha and the line, "And there's a fresh one if you mouth off again." This improvisation made Diego Luna break character as Cassian and crack a smile that can be seen in the final film.
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 Han Solo: Uma História Star Wars (2018)).
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.
In earlier versions of the script, Lyra Erso was a Jedi. This was abandoned in later versions, as the idea of exploring the lives of the galaxy's normal inhabitants, especially after the fall of the Jedi Order, was considered more interesting.
Warwick Davis: The Star Wars veteran actor plays Weeteef Cyu-Bee, one of Saw Gerrera's militia members.
Rian Johnson: Star Wars: Os Últimos Jedi (2017) writer/director plays an imperial trooper controlling the Death Star's superlaser.