When Christian Bale was 13 he travelled to China to make his first film, Steven Spielberg's Empire of the Sun (1987). The adaptation of JG Ballard's book about life in Japan-occupied China during the second world war was shot in Shanghai. It's an experience the 37-year-old Bale now finds difficult to relate to. "It was so long ago," he says, sitting back in his seat in a Beverly Hills hotel. "I feel like it was a different person who made that movie."

Bale, born in Wales to English parents, has gone on to become one of Hollywood's most sought-after actors. His career includes challenging films such as American Psycho (2000) and The Machinist (2004), as well as an Oscar-winning performance in The Fighter (2010). Next summer he reprises the role of Batman in The Dark Knight Rises, the final instalment in Christopher Nolan's phenomenally successful trilogy. No grand strategy underpins the jobs he takes. Actors, he says, "don't really have the ability to plan everything they do".

With this in mind, there is something apt about his latest film, Zhang Yimou's The Flowers of War, in which Bale's career comes full circle. The production took the actor back to China for the first time since Empire of the Sun but this time the setting is Nanking in 1937. The flowers of the title are a group of women and girls who, aided by Bale's character, try to survive the brutal treatment of occupying Japanese soldiers.

"It felt like fate calling Christian back to China," says Zhang. He and Bale are sitting in adjoining seats: Bale is wearing a dark open-necked shirt and jeans and has also grown a beard, like the one he sports at the beginning of the film when his character, an American mortician on the make, stumbles through the smoke in a ravaged Nanking to evade the Japanese. Zhang is all in black, pairing tracksuit trousers with a natty pair of Dr Martens-style boots; his daughter Mo sits between the two men and will translate for us today, as she did on the set.

Bale does not speak Mandarin and Zhang cannot speak English, so Mo was an essential presence during the shoot. The language gap did not stop the two from communicating, Bale explains, adding that he had a better experience than the last time he worked with a director who could not speak English (he declines to name the film), when the translator “told me to do the exact opposite of what the director had said”.

With Zhang, there was an immediate rapport. "You come to understand somebody, you see what they're like," says Bale. "You kind of get it. You can see expressions and body language and we were both laughing our arses off at the same thing — at least I hope it was the same thing." He laughs uproariously. "It was a real eye-opener in that I realised the communication doesn't have to be through the language. So it was very satisfactory creatively."

The prospect of working with Zhang drew him to the project. "He's a masterful storyteller," he says, acknowledging the reverence with which the director of Raise the Red Lantern (1991), Hero (2002) and House of Flying Daggers (2004) is held in China. Zhang also directed the spectacular opening ceremony of the 2008 Beijing Olympics and had been set to work with an old friend — Steven Spielberg — until the American director pulled out as artistic adviser at the games in protest at China's failure to take a tougher stance against the unfolding humanitarian crisis in Darfur. At the time, Zhang described Spielberg's withdrawal as "very regrettable" but the two have apparently remained close: when Zhang began casting The Flowers of War, he consulted Spielberg, who immediately recommended Bale.

The film, shot in a mixture of English and Mandarin, received a limited release in the US at the end of last month to ensure it qualifies for the foreign film category in 2012's Academy Awards. It will be given a wider release in February and will also be screened at the Berlin Film Festival in February, when it should be picked up for distribution in European markets.

Zhang says the story, which gives a human face to one of China's worst tragedies — the Rape of Nanking, when an estimated 300,000 people were killed in six weeks — needed to be told and needed a foreign star. "It was very necessary to have a foreign actor in the movie. During that time there were [only] a handful of foreigners living in Nanking and they played a very important role in documenting what happened."

The film was fully financed by a Chinese company, New Pictures Film — with support from two banks: Bank of China and Minsheng — but the presence of one of Hollywood's biggest stars is indicative of the close ties that have developed between the US film industry and China. Several US companies, including Legendary Entertainment, which co-financed Nolan's Batman films, have struck joint venture deals with Chinese-owned media groups to ensure their films qualify as Chinese-made productions, guaranteeing their distribution in the country. Currently, only a limited number of foreign films qualifies for official release in China because of a strict quota system, to the great frustration of Hollywood studios keen to tap one of the world's fastest-growing cinema markets.

Breaking new ground in the relationship between Hollywood and China was of no interest to Bale. "I'm no businessman, so the whole question of whether this changes the business between Hollywood and China, which some people have mentioned to me: great, good luck. But it doesn’t have anything to do with me."

His next two projects will pair him with Terrence Malick, whose last film was The Tree of Life, while the end of the Batman trilogy is clearly a matter of some relief. "It was wonderful but there's a time when everything has to finish." I ask if he is tempted to make a fourth Batman film. "No. It's the right time to exit."

Given the scale of the movies he makes and the frequency with which he works, Bale is rare among his peers in that he has mostly succeeded in keeping his personal life separate from his professional work. Apart from an incident involving an argument with a family member before a premiere a few years ago, the notoriously intrusive UK tabloids have tended to leave him alone. "I try and stay under the radar and it's working, so I'm not going to ask any questions," he says. The less the audience knows about him, the more they will appreciate the characters he plays. “You can have a pure enjoyment of the character because you know nothing about them. The less known about me, the better I can do what I do."