Rogue One: A Star Wars Story director Gareth Edwards has admitted to having a "nerdgasm" when filming with Darth Vader voiceover actor James Earl Jones.
The veteran US star voiced the Sith Lord in the original films, including 1977´s A New Hope, as well as 2005 prequel movie Revenge Of The Sith.
Gareth addressed thousands of fans at the Star Wars Celebration in London, speaking on a panel hosted by Captain Phasma actress Gwendoline Christie.
Gwendoline told the audience: "We do have confirmation that Darth Vader is in Rogue One. Gareth, can you give me a little hint, a tease about Darth Vader being in Rogue One?"
Gareth said: "I guess I got a very early Christmas present. We finished filming in December and I got straight on a plane to New York to do a voiceover recording with a gentleman called James Earl Jones."
To cheers from the audience, the British director joked: "Now, I can't tell you what role he plays in the film because I don't want to give that away."
The Rogue One director also took sound designer Matt Wood from Skywalker Sound into the studio - and said that they shared a fan moment when they heard Jones's booming voice say the word "power".
"We just looked at each other and had this nerdgasm. We were reduced to three-year-olds," he explained. "And then he looked back and we were like: 'That's great, James - let's just do it one more time.'"