'I really wanted to prepare for this, but in the end he convinced me [not to],' Tang says, gesturing towards Chan as we meet ahead of the film's gala premiere on Tuesday at the Convention and Exhibition Centre.

Chan laughs as he recalls Tang's approach towards her work on the set. 'She's still always asking a lot of questions - obviously she's still done a lot of homework,' he says. 'I think she was feeling quite insecure during the first few days of the shoot, when she was not really central to the scenes being filmed. And she was coming to me with all these queries - I remember having to hole up in my trailer during meal breaks so she couldn't find me.' The pair laugh. 'She was probably terrified working with me, as I didn't give her the direction she expected.'

'Well,' Tang says, 'I find that quite relaxing, actually. What worries me is what my next director will think of me now that I'm used to this. He might be going, 'Hey, why didn't you prepare anything before coming to work?''

Chan admits there were doubts over whether Tang was suitable for the role of a peasant. 'A lot of people said Tang Wei looked too much like an urban intellectual,' he says.

'I find that very strange - I've always been quite laddish,' says Tang. Later, she says one of her childhood ambitions was to become a 'cool, gun-toting soldier'.

Or maybe it's because Tang remains best known for her breakthrough role in Lust, Caution - a young patriotic student forced to become an ultra-feminine femme fatale, to seduce and compromise the Japanese occupying forces' Chinese spymaster during the second world war. Tang's turn as the anguished and conflicted Wong Chia-chi electrified audiences when the film was released in 2007, propelling her to international fame: she received nominations in Hong Kong (at the Asian Film Awards), Taiwan (the Golden Horses), Britain (the Baftas) and the US (Independent Spirit awards).

It's not a film Tang wants to talk about today. Asked about the impact of that role - a debut of sorts, as she only had minor parts in TV serials before Ang Lee cast her as Wong - her keenness to talk dissipates. 'It's a film and a role I like a lot,' she says, coldly. 'Everything to me is a process. If I hadn't done that, I wouldn't be working with Peter on this role of a mother in Wu Xia.'

It's hardly a surprise Tang wants to skirt around that part of her career. While the film made her an instant phenomenon worldwide, her performance - which involved explicit sex scenes with co-star Tony Leung Chiu-wai - drew heavy criticism from mainland censors.

Tang was put on a blacklist to discourage other young actresses from 'achieving fame by taking their clothes off', according to a government official. Tang found herself shunned by the industry, and her television commercials shelved. Four years on, the ban still hovers menacingly and rumours are circulating wildly about why her part in The Beginning of the Great Revival - the officially sanctioned propaganda film about the founding of the Chinese Communist Party - was edited out: she played Mao Zedong's student revolutionary girlfriend, Tao Yi.

Tang's obviously still smarting from that setback - three years passed between Lust, Caution and her second film, the Hong Kong-set Crossing Hennessy - and it probably explains the, well, caution exercised by her publicists when it comes to the press. Tang doesn't do newspaper interviews on her own - which explains Chan's presence - and her minders are quick to step in when questions drift towards Lust, Caution. Tang now has residency in Hong Kong, having applied through the Quality Migrant Admission Scheme in 2008.

As a child she harboured dreams of becoming an archaeologist but her parents pressed her to follow in her painter father's footsteps. 'They wanted me to go to the same university [my father attended], the Central Academy of Fine Arts,' she says. Instead, she took after her stage actress mother and enrolled in the Central Academy of Drama, where she studied directing after failing three times to gain entry to the acting faculty. After graduating from the academy in 2002, Tang worked in television serials until 2006 when Lee cast her in Lust, Caution - a move which propelled her from provincial obscurity to feted appearances at festivals in Venice and London.

While the fallout of Lust, Caution has hampered Tang's progress, it has also put her on a different career trajectory. After taking summer courses in Britain during the first year of her forced hiatus, she returned to the screen with productions set outside the mainland: Crossing Hennessy was soon followed by Late Autumn, an English-language, American-Korean co-production about a budding relationship between an American-Chinese ex-con (Tang) and a Korean gigolo (Hyun Bin).

As for what's next, Tang says she has no confirmed plans. 'I work more by intuition,' she says. 'It seems like whatever I plan never really works out the way I think it.'

Let's see whether Wu Xia will help lift that curse.

Wu Xia is screening now