I didn't know that, but am all the more glad for it.
Planet 51 was really enjoyable, even with a few cringe-enducing bits… there were plenty of laughs, as well as a whole plethora of amusing sci-fi/Alien jokes and a production quality and cast list on a pretty similar level to animated films being made by Pixar or Dreamworks.
Ilion Animation and HandMade Films should be proud with the finished effort, there was a lot of love and effort in evidence, even though it's not doing too well at the box office, and seems to be a bit underappreciated, they've got a guaranteed DVD purchase from me.
The art book of the film is also going to be ending up in my possession sooner or later.