Noticeable vets that are absent from the list? Tony Dovolani, who has been on the show since season two and Kym Johnson. Of course, there are still three pairs .\rbr\rbrPast mirror ball champions Derek Hough, Mark Ballas and Karina Smirnoff are among the pros returning for season 21.\rbr\rbrDANCING WITH THE STARS - SEASON 21 - BALLROOM DANCING COMPETITION The full cast was revealed on Wednesday September 2, 2015 on GMA.\rbr\rbrDWTS Season 21 Pros Revealed - GMA featuring Pros: Derek Hough, Witney Carson, Peta Murgatroyd, Val Chmerkovskiy, Artem Chigvintsev, Mark Ballas, .