Mutsuhiro "The Bird" Watanabe, the Japanese prison camp guard who tortured American prisoner-of-war Louis Zamperini, is a central character in the World War II survival story Unbroken.
But instead of casting a professional actor to play him in the movie, director Angelina Jolie picked a Japanese rock star who goes by the name of Miyavi.
The 33-year-old musician, who was born Takamasa Ishihara, admits that he almost turned her down because of his lack of acting experience, coupled with the fact that the period remains a sensitive subject in Japan, where he has a large following.
"I was scared and hesitant. This story is really controversial - the books are not even translated in Japan," he says of the story, which is documented in the memoirs Zamperini wrote before his death last year as well as in a best-selling book, Unbroken: A World War II Story Of Survival, Resilience And Redemption, by Laura Hillenbrand.
"And I had no experience as an actor," says Miyavi, who explains that Jolie was looking for someone who could command the attention of a large crowd, as The Bird had to in the prison camp scenes. "I started studying English eight years ago, so I wasn't sure I'd be able to tackle this role before I met Angie."
But Jolie convinced him the movie had a positive message and goal. "She said she wanted to create something meaningful which could be a bridge between America and Japan as well as other countries which have had similar kinds of issues and conflicts.
"So it's all about the message of Zamperini's story, which is about forgiveness and how strong a human being can be. I thought that was meaningful and worth tackling this role for, even if it meant playing such a bad guy."
The Bird is shown sadistically singling out Zamperini for punishment, beating him and forcing the other prisoners to do the same. But Miyavi and Jolie agreed that "we didn't want to portray him as a typical, one-dimensional villain".
Instead, they looked for his vulnerability and other relatable qualities, finding clues in Hillenbrand's book. "Laura said he was cruel, but also intelligent and, at the same time, lonely, sad and confused. When he was young, he also clashed with his father and did not live up to his father's expectations," Miyavi says.
An article The Bird himself wrote after the war contained insights too. Miyavi recounts: "He had been hiding in the mountains for seven years and wrote about how much he wanted to see his mother. From that article, you could see he was scared, he was struggling."
Jolie's film incorporates these humanising details into its portrayal of The Bird, which stops it from completely demonising him.
According to Miyavi, "the moment Louis enters The Bird's room, it's way smaller and simpler than he expected - one tiny bed, one tiny desk and one picture of The Bird and his father. At that moment, the audiences realise he's also a son, he's also a human being."
Another moment at the end of the film is critical as well: When the prisoners are released, they walk through a Japanese city littered with Japanese bodies. "That's not the face of a winner. There were no winners in the war - everyone was a victim. The Japanese people had to see their friends die, had to be separated from their families."
While the cast were filming in Australia, however, Miyavi got into character by isolating himself from the rest of the cast, including British actor Jack O'Connell, who plays Zamperini.
The ice was broken only at a party held after their scenes together had been filmed.
Miyavi recalls: "Most of the actors from the prison camp scenes were leaving, so before we left, Angie said she wanted to bring my performance to the crew because they had no idea what I did.
"So she called my drummer and my staff from Tokyo to Sydney and we had a gig. And everyone was dancing, Angie was dancing," he adds with a smile.
Miyavi performed a few of his signature electro-rock tunes, which feature the trademark guitar string-slapping style that has earned him the nickname The Samurai Guitarist.
O'Connell joined him on stage for a few tongue-in-cheek cover versions, including Folsom Prison Blues by Johnny Cash and, to serenade their director, Angie by The Rolling Stones.
This bonding moment with his co-star - whom he admits he had trouble understanding sometimes because of his strong northern English accent - was one of the highlights of making the film.
"On set, we were separated, but with music, we were able to get together. That was a great moment."