Julianne Hough is returning to the ballroom! The longtime pro will be taking a seat behind the judges' table once again for the show's season 30 finale.Julianne will be sitting in for her brother, judge and former pro Derek Hough, who is still in quarantine after testing positive for COVID-19 last Tuesday.ET has learned that, while Derek is under quarantine and recovering, he will still very much be a part of the show, appearing virtually as well as in a pre-taped segment.Julianne is a two-time