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Director David Dobkin had a difficult time choosing a suitable Asian actress who could do movement work, emote well, and speak decent English. He then saw clips of Fann Wong's videos Heroes in Black (2001) and Legend of the Snake Spirits (2001) and requested to audition her in London, which she did attend. She subsequently got the role and her number of scenes was increased by thirty percent.
There are several references to Sherlock Holmes in this movie. One of them is that the "bad guy" is named Lord Rathbone. Basil Rathbone was one of the first actors to play Sherlock Holmes in a movie.
When Artie Doyle tries to break the lock of Madame Tussaud's, Roy compares his work to that of a surgeon. This is probably a reference to the fact that the real Sir Arthur Conan Doyle was a physician, even though in the movie he's a detective.
Lord Rathbone in the movie is referred to as "the finest swordsman in England". Basil Rathbone was the star of many swashbuckler movies, and was considered the finest swordsman on the silver screen.
This movie marks the first on-screen battle between Jackie Chan and Donnie Yen, who have had success in Hong Kong, but had never fought each other before on-screen.
Fann Wong (Chon Lin) trained for her stunts despite not having a martial arts background. She has a background in ballet, which helped to a certain extent.