We all know the celebrities on ABC's hit show Dancing with the Stars spend hours upon hours practicing their routines each week -- but what do they do during their downtime!?  Chelsea Kane and her partner Mark Ballas along with Lil' Romeo and his partner Chelsie Hightower remix songs! 

Seriously though -- during a recent rehearsal break, Chelsea + Lil Romeo' belted out their own rendition of Rebecca Black's tune Friday!  You must watch the hilarious video! 

Related Article:  Chelsea Kane Dances to Panic! At The Disco!

By the way -- who knew Mark Ballas was such a talented beat-boxer.  And, is that a tiny cameo by Pia Toscano we see hanging out with the foursome!?  You know, Mark's rumored GF & American Idol cast-off?  It sure is!  Interesting

What do you think of the group's Friday remix!?  We think it is pretty darn funny!