Could be real or fake, but is still quite cool. This is touted as the test footage for the binned CGI movie.
"Hey gang! I've got an interesting little video to show you today that may or may not be actual test footage from Warner Bros. CGI feature film adaptation of the classic 1980's animated TV series Thundercats. It's got the WB logo on it, but this could still easily end up being a fan-made video. The character designs seem to match up with some concept art from the film that leaked online back in 2009 though.:Source: GeekTyrant
As of right now the Thundercats feature film is on hold, and there is a new animated series that's being developed in preparation for the film. There's no word on how old this footage is, but if it's real I imagine in was made around the same time the concept art leaked out online.
This isn't top quality CGI animation, this is just some decent concept footage thrown together by the studio or a fan to give us a glimpse of what a CGI Thundercats movie might look like. Watch the footage below and tell us what you think!
Here's the concept art that was leaked in 2009 over at MovieLine"