Update: Ubisoft has released the following statement –

“An internal video showing images of Rayman Origins’ sequel has leaked over the Internet. This video was intended as a purely internal demonstrative video, and in NO way represents the final game, the final console or their features. This video was destined for internal production teams who often create game prototypes with work in progress development kits. Ubisoft confirms the development of Rayman Legends handled by Michel Ancel and his team in Montpellier.”

You must check out this trailer!