The show's official Facebook page confirmed that the cast will be unveiled on Friday, July 27.
Season seven competitor Misty May-Treanor has already campaigned for a slot on the All-Star season and Kate Gosselin is also rumoured to be returning.
Chelsea Kane, who finished third in season 12, has suggested that she likely won't appear on Dancing with the Stars: All-Stars because it might not top her initial time on the series.
Kane explained in May: "It was such an amazing experience and I had such a good time and I got so lucky that it would be fun to go back and try it again.
"But at the same [time], it's like, the sequel is never as good as the [original] movie."
Dancing with the Stars returns this fall on ABC.