Due to Mallika Sherawat's racy image in Bollywood, rumors circulated that she landed the role over many other Indian actresses (Aishwarya Rai Bachchan, Lara Dutta, Priyanka Chopra) because she was willing to do full frontal nudity in this film. When these rumors were spread, director Stanley Tong and Jackie Chan held a special press conference in India to say that they picked Sherawat over many others because of her great charm and genuine acting talent, and that the film did not even have a kissing scene, let alone full frontal nudity.
Hee-seon Kim, one of the female leads, is from Korea. She learned her Chinese lines by memorizing the sounds. At times, production would change the script a little, but had to keep Hee-seon's lines about the same because of her limited Chinese.
(at around 56 mins) When Jack is talking on the phone in the car, his contacts display lists "Stanley Tong" as a contact. Stanley Tong was the director of this film, and he is also credited for numerous behind-the-scene roles.
In the outtakes, Jackie Chan fights with his rival who is on wires, but does not use any himself. He overdid a sweep kick and fell off the scaffold about fifteen feet to the ground onto a mattress. The outtakes show him falling and climbing back up to do the scene again.