Nicole Kidman and Hiroyki Sanada joined producer Chris Brown for an intimate screening of “The Railway Man” Tuesday evening at the Soho House West Hollywood.

While a shy Kidman kept her comments brief and simply thanked the audience for coming, she set the tone for the screening by saying just a few words about working on the project.

“It was harrowing,” said Kidman, who plays the wife of former British solider Eric Lomax, who was tortured as a prisoner of war during World War II.

Following the screening, attendees made their way to the cocktail reception where Brown and Sanada posed for photos, mingled with guests and discussed their passion for this project.

For Sanada, being a part of telling this true story was also an opportunity to “reexamine history.” After reading the script, he said he was drawn to the controversial topic the film addresses and knew he had to play the role of Japanese soldier Nagase.

“I thought this role must be played by a Japanese-born Japanese (actor) and we should release it in Japan,” Sanada explained.

The film was also shot in many of the locations where the real life events actually took place, which Sanada said added a positive energy to the set. “It felt like I heard a voice (saying), ‘Please tell our story to the world to make a better future. Don’t waste our experience,’” he said.

Brown echoed this sentiment as he told Variety about the process of searching for locations.

“There are lots of these ravines – gorges that have been built by hand. They were built by hammer and chisel by these guys dying on the rock. You go to these places… and they just have an energy about them that is so dark,” Brown said. “I was in one of these and there was a sign that said ’28 men were beaten to death on this spot.’ You suddenly realize how extreme and how bleak it was.”

Sanada, who shares nearly all of his time onscreen with star Colin Firth as Lomax, said working with Firth was often like a two-man show.

“I really enjoyed collaborating with him,” Sanada shared. “We are the same age, so we could create a good chemistry from the beginning. Also, he’d done a lot of theater too, so every take was like a live session.”

Brown also said that the specific pairing of Sanada and Firth added another dimension to the film’s message, which he said applies to all wars.

“One of the great things was to actually perform that almost ritual of forgiveness with a Japanese actor and with an English actor in that place where so much hatred and so much violence had been done,” Brown explained. “It was actually only while we were doing it that we suddenly realized that there was almost a bigger importance to what we were doing beyond the film itself.”

Sanada said he still cries during each screening as the final scene depicts the emotional reconciliation between Lomax and Nagase.

“We have to tell this story generation to generation,” Sanada said. “That’s the important thing – never forget and never again. I think that’s the mission of the movie.”

Even though the film’s topic may be controversial, Sanada said it’s still a story that needs to be told.

“Good medicine is always bitter, but we should take it,” he said.

The Weinstein Co.’s “The Railway Man” bows in theaters April 11.