Watch Jack Black And The JUMANJI Cast Serenade The Japanese Media

Months of following Sony Japan on YouTube has finally paid off. When I first followed the channel, I did it because I began to notice that American actors typically act weirder for the media overseas than they do for us. I've been patiently waiting for one that's humorous enough to share, and today, it finally happened. Of course, Jack Black is always good for a bizarre celebrity interview, but how often does he manage to get his costars to go along with it as The Rock, Nick Jonas, Karen Gillan, Kevin Hart all join him in singing "Jumanji." 

People who have seen the movie, is this in the actual film, or did they just make this up before appearing in front of the press that night?