Christian Bale is not a chatty actor.

It's difficult to pull answers out of the usually serious guy.

But at the Four Seasons hotel in Beverly Hills, when we meet to discuss his new film The Promise, the 43-year-old Briton actually seems happy to talk.

Perhaps the seriousness of the historical drama – set against the backdrop of the Armenian genocide during and after World War I – requires some lightness, or maybe he's just become a little more comfortable doing press interviews.

He's casually dressed, the movie star beard in place, as is the sexy Welsh accent, and he actually smiles once in a while.

When asked why he chose this role, Bale even laughs and jokes that his American wife of 17 years, Sibi, picks them for him.

He said: "She is a large part of that – if she gives the nod of approval or not on it.

"It's a lot like my approach to acting. I don't know anything about acting, I just know about the characters that I play.

"So it's the same thing with a script. Does it stick in my head? That's really it.

"Do I keep thinking about it afterwards? I purposely try to forget about it and then the ones that keep hammering away in my head or making me sit up at night thinking about, those are the ones I want to work on."

Opening here on June 22, The Promise sees Bale playing a photojournalist who is involved in a love triangle.

It's certainly a far cry from the role he is best known for, Batman, which he has played three times in The Dark Knight trilogy.

On the eve of WWI, Chris Myers (Bale) arrives in Constantinople accompanied by his Armenian lover Ana (Charlotte Le Bon) to cover the chaos that has consumed the city for the Associated Press. When she meets medical student Mikael (Oscar Isaac), their shared heritage leads to an attraction that explodes into a romantic rivalry between the two men.

Meanwhile, the Ottoman empire has turned against its ethnic minorities, leading to one of the least known tragedies in history, as 1.5 million Armenians are exterminated.

Turkey has always denied its role in the genocide, which has all but disappeared from history books.

All profits of this US$100 million (S$138.4 million) epic have been pledged to charity.

Bale admits he wasn't aware of the Armenian genocide before doing The Promise.

"To my shame, I knew nothing about it when I first got sent the script."

Despite the controversy that still exists, he remains very comfortable with his choice.

"In doing the research, it seemed to become clear to me that it was the right thing to do. And I certainly wouldn't feel good about myself if I shied away from doing the right thing.

"Did I have some people say to me, 'Come on mate, you don't want to get mixed up in that, don't bother'?

"Yeah, people were saying that. But every time anyone says don't do something, I always want to do it more."

The research – including conversations with experts and watching related documentaries – was considerable.

"I couldn't get through all of the books that I was given to read. I was given a library, and I am a slow reader…

"(Director) Terry (George) and I would have dinner the night before filming another scene, and he would give me a (thick) book and go, 'Oh, here's a bit of reading before you fall asleep'. That didn't happen," he says wryly.

Bale, who lives in Los Angeles, also feels strongly about the importance of journalism in the world, especially today with US President Donald Trump in the White House.

"Listen, there's never been a more vital conversation about the need for great journalism and for the real versions of the Chris Myers of the world, since a certain individual became the leader of our country."

What will be interesting for Bale's fans is to see him in his next role, that of former US vice-president Dick Cheney in an untitled biopic written and directed by Adam McKay, who in 2015 worked with Bale in The Big Short.

Cheney has often been referred to as Darth Vader by his detractors, and this has to be a script that kept Bale up at night to make him take the part.

http://www.tnp.sg/entertainment/movies/christian-bale-sheds-light-forgotten-tragedy-promise