Uniting two of Asian cinema’s most legendary action heroes in the same movie for the first time, The Forbidden Kingdom includes a sight none of us expected to see. It’s not the fight between Jackie Chan and Jet Li — that was bound to happen eventually, though judging by their diminished agility here, you’ll wish they got around to it 20 years ago. No, it’s the regrettable piece of low comedy when Li pees in Chan’s face. This uninspired adventure movie does much the same to action fans, albeit metaphorically.

Though The Forbidden Kingdom pilfers freely from Drunken Master, Iron Monkey and The Bride With White Hair, it all adds up to a forgettable variation on The Karate Kid due to its lacklustre action scenes, plodding narrative and charmless young hero. Michael Angarano plays a Boston teen who’s teleported into an ancient kingdom where he must assist a wine-swilling immortal (Chan) and a warrior monk (Li) in a quest to defeat a venal warlord. In the wire-fu fights that ensue (choreographed by the equally legendary Woo-ping Yuen), director Rob Minkoff definitively proves he’s no Tsui Hark — poorly shot and edited, the martial-arts action is rarely as rousing as it ought to be. The dramatic scenes are worse, what with Li and Chan’s awkward attempts to banter in English. The aforementioned instance of urination only adds to the feeling that the opportunity for greatness has been pissed away.