Jet Li also plays the Monkey King in the film.

The good news for kungfu enthusiasts is that fight scenes take up a lot of screen time. There are a variety of kungfu styles on show, including the crane and tiger fist, no shadow kick and drunken kungfu. Minkoff grew up in the bay area of San Francisco. Like Jason in the film, as a little boy he went to China town a lot. But what piqued his interest in Chinese culture were kungfu films.

"In Chinese kungfu movies, typically two things are being expressed," he says. "One is the physical act of the fighting, and the spiritual side of the teaching, involving experience and conscience."

Minkoff's first Chinese kungfu film was King Hu's Come Drink with Me (Da Zui Xia), in 1966. He is fond of Bruce Lee and Shaw's films, too. In The Forbidden Kingdom, he goes out of his way to pay tribute to the old kungfu films.

Chan's drunken wanderer is a nod to his 1978 film Drunken Master (Zui Quan), while the silent monk Li reminds many of his character in The Shaolin Temple (Shaolin Si). Young actress Liu Yifei's supporting role as Golden Sparrow is inspired by Pei-pei Cheng's character in Come Drink with Me, while the white-haired witch is almost a replica of Lien Ni-chang, the heroine in Ronny Yu's The Bride of White Hair (Baifa Monu Zhuan).

The battles between Li and Chan, choreographed by Yuen Woo-ping, give each a chance to express his different style and personality.

"Jet was serious. He has learned traditional martial arts from a very young age, while Chan was hilarious and lighthearted," Yuen says.

"He can do a bit of everything," Yuen says.

In Minkoff's eyes, the two superstars are just like Buddha and his disciple.

"Li was like a disciple of the Buddha, but Chan is the Buddha himself," he says. "Jet is very serious and religiously dedicated to Buddhism. Jackie is not, he is free, always bringing happiness to people around him."

The crew took part in a big ceremony for the opening of the film, which was a very traditional Chinese gesture to pay tribute to the Buddha. As Minkoff recalled, Chan was quite lighthearted about it, while Li was serious and dedicated.

The two's cooperation, says Minkoff, is like the Beatles. Each is good, but when you put them together, it is magic.

"It's history. As time goes on, it will become historic. Even if you do it again, this is the first time," he says.