“Since the release of Kung Fu Panda, there has been one burning question that people are desperate to answer,” says director Jennifer Yuh Nelson. “The question that defies explanation is: Why is Po’s dad a goose?”

It’s a head-scratcher, to be sure, especially since the Po in question is that film’s eponymous panda. An irksome conundrum, and a fittingly oddball one for a film that came out of nowhere and surprised even the most ardent Pixar fans with its creative animation and winsome storyline.

Released in 2008, Kung Fu Panda amassed a colossal $633m worldwide, garnered warm reviews (“A master [course] in cunning visual art and ultra-satisfying entertainment,” said TIME) and landed an Oscar nom in the Best Animated Feature Film category.

A return trip to ancient China and the world of Po (Jack Black) was pretty much a sure thing – and the seeds of a sequel had already been sewed in that paternity mystery.

“For Po, the Dragon Warrior, it was logical for him to finally realise his father is not his biological father and to seek his origin,” agrees Nelson. Adds producer Melissa Cobb: “We always imagined we had more story to tell with the continuation of Po and his journey…”