Making their escape in a small boat, the two friends and their new equine pal wash up on the shores of Central America. Recognising one of the features on their treasure map, they strike out for what they believe is fortune but end up hopelessly lost in the jungle. Eventually, they are captured by a group of Indians and carried back through a secret gateway behind a waterfall into the legendary El Dorado, where High Priest Tzekel-Kan (voiced by Armand Assante) pronounces them to be the gods foretold in local legend. In fact, however, Tzekel-Kan plans to used his newly discovered deities as a way of taking power from the Chief (Edward James Olmos).

Tulio and Miguel, meanwhile, enter into an uneasy partnership with the young Aztec girl, Chel (Rosie Perez), whom they had earlier rescued and who is desperate to escape from the closed city of El Dorado. She agrees to preserve the fiction that they are Gods, while they in turn promise to take her along when they go, carrying with them a fabulous cargo of gold ‘offerings’ befitting such divinities.

But making two distinctly unheroic characters the heroes of the story was not the only innovation for Katzenberg (who executive produces The Road to El Dorado) and his team - producers Bonne Radford and Brooke Breton; and directors Eric ‘Bibo’ Bergeron and Don Paul. They were determined to break the mould in other areas, too. The first changes came about when Branagh and Kline were recording their lines. As with every major animated movie, the voice work for The Road to El Dorado was done well in advance: that way, the animators can match the characters’ mouth and other movements to the dialogue track. What was different here, however, was that Branagh and Kline recorded their voice tracks at the same time, giving them a more than usually large input into both the characters and even their dialogue.

“Kevin and Kenneth are such great talents, and each has an incredible sense of humour,” says Katzenberg. “Ken is very dry and witty, and Kevin is a natural comedian. They had such terrific chemistry, and it was marvellous to put them together and see what happened. We were able to incorporate a lot of their personalities in their characters because, like Tulio and Miguel, they are something of an odd couple.”

French-born director Bergeron, whose animation track-record includes such films as The Adventures of Pinocchio and The Goofy Movie, found the process especially helpful. “Kenneth could go to the microphone and immediately give me 15 separate interpretations of a single line,” he says. “He’s amazing. Any nuance we could possibly have needed was in the performance he delivered. For his part, Kevin would constantly try variations on his lines and came up with some wonderful gems. In some cases, we ended up using his ad libs, which are some of the funniest lines in the film.”