At one point, Park has to give Hiddleston a chop-heavy back massage in order to get the right sounds of him.
Voice acting can be challenging for screen actors, often requiring the kind of extreme, over-the-top delivery that they look to avoid when working on a live-action project.
The film is in cinemas 26 January.
This is clear in a behind-the-scenes look at upcoming Ardmaan stop-motion animation Early Man, which The Independent brings you exclusively today, seeing Eddie Redmayne, Tom Hiddleston and Maisie Williams trying to get their mouths around the dialogue Wallace and Gromit director Nick Park has given them.