How Gwendoline Christie trained for her 'Star Wars: The Last Jedi' battle scenes

The "Game of Thrones" actress opens up about the new film.

"What I can tell you is that I was reunited with C.C. Smiff -- he was the man who gave me the confidence and the skills and worked with me for months beforehand and taught me to fight and sword fight," Christie said.

Smiff also worked with Christie on "Game of Thrones."

Captain Phasma, Christie's character, and Finn, played by John Boyega, have an intense battle scene in the new movie. Christie gushed that Boyega "has this vital energy that just really inspires everyone around him."

Despite her packed production schedule with "GOT," Christie said she was "relentless" in trying to land a role in the new "Star Wars" films.

"I'd wanted to be in 'Star Wars' my whole life," she said. "Then when I heard this was coming back, you know, I was cheering on with the rest of the world thinking we're going to have it again and I really wanted to be a part of it and also when I saw how diverse the casting was, that's what excited me."

She added, "I was very lucky to hear that they were interested."

Captain Phasma perfectly suited Christie's expectations for a strong female character, she explained.

"They had decided to create this female character who looked incredible but her femininity is not delineated in the shape of her body," Christe said.

"The Last Jedi" will be in theaters nationwide on Dec. 15.

ABC News and Lucasfilm Ltd. are both part of the Disney Co.