Brendan Fraser was Author Cornelia Funke's personal choice for the role of Mo, as he was her inspiration for the character. She even dedicated the second novel of the trilogy to him and sent him a signed copy. The producers originally wanted a bigger Hollywood star, but on the insistence of Funke, they gave in and accepted him in the role.
In an early scene at Aunt Elinor's (Dame Helen Mirren's), a toolkit is seen next to Brendan Fraser. It is the same toolkit Rick (Fraser) gives to Evie (Rachel Weisz) in The Mummy (1999).
When writing the novel, Cornelia Funke envisioned the character of Dustfinger as somewhere between Viggo Mortensen and Daniel Day-Lewis.
The Italian Riviera Film Commission helped to find an abandoned and suitably spooky town to serve as Capricorn's (Andy Serkis') lair.
Cornelia Funke visited the set several times, to the great joy of producer and director Iain Softley, who was proud of seeing Funke's pleasure at seeing her words come to life.