Bryan's participation was revealed on "Good Morning America" Monday.
Viewers had a choice of bringing Bryan, Carson Kressley or Kyle Massey back for the all-star edition of the show.
The former "Cheetah Girls" star received the most votes and will be paired with professional dancer Louis Van Amstel, who is returning to the show for his ninth season.
Former "DWTS" contenders Bristol Palin, Joey Fatone, Kirstie Alley, Apolo Ohno, Gilles Marini, Melissa Rycroft, Pamela Anderson, Kelly Monaco, Shawn Johnson, Helio Castroneves, Drew Lachey and Emmitt Smith were announced as cast members of "All-Stars" last month.
"DWTS" veterans Tom Bergeron and Brooke Burke-Charvet will return as co-hosts of the show.