[]Pratchett, who has a cameo in the film's opening scene, is delighted with the casting of Jason, despite many fans expecting a younger, slimmer actor. “It was mainly the book cover illustrations that did that,” he insists. “I'm very good at not describing characters. David Jason has got three amazingly good attributes. Firstly, he is an excellent actor. Secondly, he's Sir David Jason, and that name counts for something. And thirdly he's a Discworld fan and about 15 years ago he declared that he wanted to play Rincewind. I thought, ‘Wonderful!'”