is right around the corner, and it's going to be one you definitely don't want to miss!In addition to the four finalists giving it their all in the last-chance Freestyle round, judge Derek Hough will be taking the stage for a second time this season (this time solo!), while Nelly will perform a medley of his greatest hits on top of his dance routines with Daniella Karagach.But that's not all — a number of celebrities from the season 29 cast will be back in the ballroom Monday night, to cheer on