Director Feng Xiaogang's earthquake epic Aftershock is closing in on China's all-time box office record - but rather than rejoicing, the production house behind the film is starting to sweat.
Such has been the unprecedented interest in the fortunes of the film - following the director's boast last year that it would become the first-ever Chinese production to surpass 500 million yuan (56 million euros) - that producers and co-distributors the Huayi Brothers are remaining tight-lipped about just how and where the money is coming from.
Aftershock - which follows the fortunes of a group of survivors of China's 1976 Tangshan earthquake - opened on around 4,000 screens around China on July 22 and has now collected more than 400 million yuan (45 million euros) overall.
That figure includes receipts from China's IMAX theaters which - for the very first time - opened a film at same time as regular cinemas.
IMAX screens picked up 4.3 million yuan (480,000 euros) on the film's opening weekend - from its overall 160 million yuan (18 million euros). But Huayi Brothers have this week refused to be drawn on the make-up of the film's now-400 million yuan (45 million euros), telling the film industry website Film Business Asia (http://www.filmbiz.asia) it had become a "very sensitive subject.''
There has been some controversy over Chinese box office figures in recent years - for both local and foreign releases - with some studios being accused of inflating numbers to grab more headlines. The raw data, meanwhile, is usually released by the Chinese government.
The previous highest-grossing Chinese film was last year's The Founding of a Republic - made to mark the 60th anniversary of the founding of China's People's Republic - which took in an estimated 410 million yuan (46 million euros). Avatar sees the all-time record for any film released in China by earlier this year raking in around 1.3 billion yuan (145 million euros).
Meanwhile, the Hollywood box office smash Inception - which has now collected an estimated US$370 million (280 million euros) worldwide has had its mainland China release date brought forward by almost a month - to September 2 - to avoid running into local productions which will be released for the country's "Golden Week'' of holidays which begin with the October 1 National Day.
The period is traditionally a peak time for films in China as families gather for a week of feasts and celebrations.