Usually the Miley and Mandy Show videos require no introduction, but this one needs a little background info...  Apparently it is a new trend on YouTube for celebrity dancers to go around challenging each other to video battles.  So Jon M. Chu, director of Step Up 2: The Streets and star Adam Sevani challenged Miley and Mandy to a dance battle.  Here is their original video:
Miley and Mandy responded with this video, which includes Step Up stars Channing Tatum and Jenna Dewan:
 
 
 



