Original reports on who would be playing the body of Darth Vader in the upcoming Rogue One: A Star Wars Story intially pointed to prequel actor Hayden Christensen. FlickeringMyth (who prior to Batman v Superman ran a correct article on the character Scoot McNairy would be playing) recently got their hands on information claiming that British actor Spencer Wilding would be donning the classic Vader suit in the film.
Wilding has had few roles outside of stunt-work in movies like Batman Begins, Ghost Rider: Spirit of Vengance, Guardians of the Galaxy, and Wrath of the Titans.
Their source also claims that Wilding is running lines while filming, indicating that Darth Vader will also have a speaking role in the film. It is unconfirmed now whether James Earl Jones will be returning as the voice of Darth Vader, but since he is doing the voice on the Star Wars: Rebels television show one would expect him to do it again this time around.