“They said, ‘Oh, Gareth wants to see you and talk to you and say welcome,’” he recalled in a clip from PEOPLE’s Special Report on the PEOPLE/Entertainment Weekly Network (PEN). He then heard Vader’s iconic breathing and turned to see the Sith Lord walking towards him.
“I started shaking,” Luna said. “I felt like I was 6 years old, and I just turn and there he was. He was so scary.”
Watch his story in the clip above.
Luna plays an intelligence officer named Captain Cassian Andor in Rogue One, which tells the story of how the Rebel Alliance acquired the plans for the Death Star, thanks to the efforts of a small squadron. Along with director Gareth Edwards and cast members like Felicity Jones (Jyn Erso), Ben Mendelsohn (Orson Krennic), and Donnie Yen (Chirrut Imwe), Luna takes fans behind the scenes of the long-awaited Star Wars anthology film on PEN.
Rogue One hits theaters on Dec. 16. Watch the full PEN Special on Rogue One, streaming now on People/Entertainment Weekly Network. Go to PEOPLE.com/PEN, or download the app for Apple TV, Roku, Amazon Fire TV, Xumo, Chromecast, Xfinity, iOS, and Android devices.