Arthur and the Invisibles

Arthur et les Minimoys (2006)
written and directed by Luc Besson

animation combined with live-action sequences

Freddie Highmore plays Arthur
Mia Farrow plays his Grandmother (!)

real-estate developers want to demolish their house
Arthur decides he can save the day by finding the treasure of the Minimoys (those tiny beings you see in the trailer)

voices only:
Jimmy Fallon (Bétamèche), Madonna (Selenia), Robert De Niro (King), Harvey Keitel (Miro), Chazz Palminteri (The Travel Agent), Emilio Estevez (Ferryman ), Snoop Dogg (Max), Jason Bateman (Darkos), David Bowie (Maltazard)

The PlayStation 2 video game that came out in conjunction with the movie recreates the adventure of young Arthur and his friends, Selenia and Bétamèche.