Smirnoff, who won the coveted Mirrorball Trophy with soap star J.R. Martinez in Season 13, took last season off to focus on other projects, including promoting her book, We're Just Not That Into You: Dating Disasters from the Trenches, and filming the indie pic Tango Shalom.
She told EW that she was "nervous about not dancing" for a season. "I had other things to do in my life," she said. "but not going back to the show felt like trying to see if I can walk on my own two feet! I've had obvious moments when I missed it."
Stay tuned to see who will be joining the cast of Dancing with the Stars Season 21. Good Morning America is expected to make the big reveal during the first week of September.
Are you excited for Karina's return? Who would you like to see her paired with?
Dancing with the Stars returns Sept. 14 on ABC.
VIDEO: TVGuide.com editor Robyn Ross dances with Derek Hough!