Other actors include Chinese action actor Zhang Jin, who has won several national championship titles, and Thai actor Tony Jaa, a muay thai black belt holder.

But Wu, especially, knows pain pays.

The 41-year-old's two latest films－the special forces-themed 3-D blockbuster Wolf Warriors and SPL2－have earned him the title of the "1 billion king", since both films have together grossed more than a billion yuan.

Some posts on major film review websites－which score SPL2 at 7 out of 10－call Wu's performance a "breakthrough".

Entertainment media often compare Wu with Li Lianjie, known as Jet Li in the West.

Wu began training at age 6 and won six national wushu championships from 1984 to 1994.

Both Beijing natives began learning kung fu as kids in the same school in the capital and shot to fame with Hong Kong titles later. Some critics say unfortunate timing is the main obstacle Wu has faced in reaching the stature of Li, who's 11 years his senior.

Kung fu flicks have declined in popularity since the late 1990s. Viewers got bored with coarse productions, repititious and absurd plots.

"Screen titles produced like fast food will eventually ruin moviegoers' appetites. Only the good stories and realistic fight scenes can remain evergreen in the market," Wu says.

He hired four scriptwriters to revise the plot of his directorial debut, Wolf Warriors, 18 times.

He stayed about 18 months with real special forces for the film, which came in as a dark horse to top the Tomb Sweeping Day holiday.

"So many years have taught me action filmmakers need patience. They must wait and take lessons from time," he says.

"You can handle complex characters after you're mature. There is more to heroes than their ability to issue and receive punches－there's more in their hearts."