Christian Bale has said he found it hard to watch the amount of crying his young co-stars had to do in his latest movie.
The Oscar-winning actor is in Beijing to promote a movie set during Japanese army's brutal rampaging of China's wartime capital, known in the West as the Rape of Nanking.
The Batman star plays an American priest in the film The Flowers of War, directed by one of China's best known modern filmmakers, Zhang Yimou.
It is an adaptation of a Chinese-language novel by contemporary writer Yan Geling about 13 sex workers in Nanjing who volunteer to replace university students as escorts for invading Japanese soldiers. In the novel that translates roughly as The 13 Women of Nanjing, the American priest leads a church that shelters prostitutes and young female students during the invasion.
Bale praised the ability of the actresses who play the young students in the movie to act fearful and upset for extended periods of time.
"Poor girls, they were always crying their eyes out," the actor said. "When I first arrived, I felt: this is just not good. I don't like that - the girls having to be upset for 10 hours a day. They were crying their eyes out for 10 hours a day, I don't know about you but for me it was exhausting - it makes you ill.
"But they were actually really good actresses because they could suddenly stop and kind of go 'hahaha, we can be like that' and I was so happy to see that."
Director Zhang said he wanted to show the "brilliance of humanity in a circumstance of war" through the dramatic story.
"I think as long as the story is moving, people from all over the world will like it," he said.