The 41-year-old actor from Chongqing says the most challenging part during filming was language training.

"I had to learn Thai and Korean. Thai is pretty difficult to pronounce, and I was strictly required not only to speak it correctly but to say it naturally, just like my mother tongue."

Wu says: "One of the biggest riches that Hong Kong movies bring to the world is kung fu films. I hope the rising number of recent action titles, such as SPL2, shows that the genre is enjoying a resurrection in the booming market."

The first installment of the SPL franchise, starring action stars Donnie Yen and Sammo Hung, has topped the box office for several weeks since its release in Hong Kong earlier this year. But it has yet to be introduced on the mainland because it is deemed to be a production with "too much violence" in it.

Yu Dong, CEO of Bona Film Group, one of the film's producers, says the second installment will take that into account while providing a visual feast for kung fu lovers.