Zebedee (Sir Ian McKellen) is the only character to not have his voice redubbed for the American release. While Kylie Minogue still voices Florence, she redubbed her voice with an American accent.
In the original trailer, Doogal's voice was provided by an adult. In the final movie, he was voiced by child actor Daniel Tay. The actor who voiced Doogal in the trailer has yet to be identified.
This movie was conceived when Harvey Weinstein acquired the rights to The Magic Roundabout (2005). He approached Butch Hartman to re-work the movie, who came up with an idea to have the movie interlaced with live-action sequences akin to that of The Princess Bride (1987). Hartman felt this would improve the original movie, which he thought was boring. However, these sequences were cut due to budgeting reasons. According to Hartman, much of the material which he had re-worked had been re-re-written by new writers, stating that he had "three percent" to do with the finished product.
Three to five minutes of footage from The Magic Roundabout (2005) was cut out of the movie, including a dream sequence.
There are a couple of instances in the movie where the original British voices are still present. When Brian bites Zeebad's arm, Tom Baker's original voice can be heard yelling "Ow". When Brian is launched into the air after Dylan presses the button to the ejector seat, Jim Broadbent's scream can be heard. And Joanna Lumley's operatic singing is heard during Ermintrude's rehersal and when she's breakes the ice during the climax. A few of the British voices can also be heard in the trailer.