The All-Star announcement was made on "Good Afternoon America." These fan favorites and past winners will be headed to the ballroom in just a few short weeks.
Olympians and former "DWTS" winners Apolo Ohno (Season 4) and Shawn Johnson (Season 8) will show off their fancy footwork again this season, along with fellow champs from seasons' past: former 98 Degrees member Drew Lachey (Season 2), former Dallas Cowboy star Emmitt Smith (Season 3), Brazilian race car driver Helio Castroneves (Season 5) and soap star Kelly Monaco (Season 1).
Actresses Pamela Anderson (Season 10) and Kirstie Alley (Season 12), French actor and finalist Gilles Marini (Season 8), and former 'N Sync singer Joey Fatone (Season 4), are also among this season's high-wattage alumni in the competition.
Bristol Palin (Season 11), daughter of former Alaska Gov. Sarah Palin, and TV personality Melissa Rycroft (Season 8) round out the pack.
Another first in "Dancing" history, the 13th contestant will be decided by America in an online vote. Fashion commentator Carson Kressley (Season 13), singer Sabrina Bryan (Season 5), Disney Channel star Kyle Massey (Season 11) are vying for people's votes to score the 13th spot in the competition.
The alumni's professional partners were not announced, but will be revealed Monday, Aug. 13 on "Good Morning America."
The stars, the drama, the glamour and the glitter are back on ABC when Dancing with the Stars returns on September 24 at 8pm.
Meet Season 15's All-Star Cast
Shawn Johnson, Season 8
Former Olympic gymnast Shawn Johnson transitioned seamlessly from the balance beam to the ballroom and won season 8 with pro partner Mark Ballas. Johnson narrowly beat out French actor Gilles Marini to win the mirror ball. Johnson could not attend the announcement since she was in London at the Olympics.
Pamela Anderson, Season 10
Actress and model Pamela Anderson sizzled on the dance floor on season 10. Though she was eliminated in week six of the competition, Anderson will be sure to add sex appeal to the all-star lineup.
Kelly Monaco, Season 1
The "General Hospital" star and model was "Dancing's" inaugural winner in 2005. Monaco narrowly escaped a wardrobe malfunction after her dress strap broke mid-routine.
Bristol Palin, Season 11
The "Life's a Tripp" reality star and daughter of former Alaska Gov. Sarah Palin was one of the most talked about contestants of season 11. Palin and pro partner Mark Ballas made it to the finals amid controversy. Though she consistently scored at the bottom of the leader board based on judges' scores, Palin was voted back week after week, causing some viewers and critics to accuse her mother's Tea Party supporters of stuffing the ballot box for the younger Palin to stay on in the competition. Palin brushed off her critics and will continue her "Dancing" run this season.
Melissa Rycroft, Season 8
The TV personality and new mom rocketed to fame after her reality TV relationship on "The Bachelor" crumbled in front of television audiences. Rycroft was tapped to replace injured season 8 contestant Nancy O'Dell at the last minute and the rest is history. Instantly a fan favorite, Rycroft and her professional partner Tony Dovolani placed third overall.
Kirstie Alley, Season 12
Actress Kirstie Alley came in second with partner Maksim Chmerkovskiy, losing out to NFL star Hines Ward. A fan favorite, Alley gained dancing prowess week after week and lost a remarkable amount of weight on the show. On the season 12 finale, she showcased a much slimmer figure, wearing the same costume from the show's premiere night that had reportedly been taken in 38 inches to fit her new frame.
Drew Lachey, Season 2
Delivering consistently energized performances, the former 98 Degrees member was an early front runner and went on to win the second season of the show with pro-partner Cheryl Burke in 2006. His country freestyle to Big & Rich's "Save a Horse, Ride a Cowboy" is one of the most memorable dances ever and was voted the No. 1 dance of all time by fans in 2011.
Emmitt Smith, Season 3
Former Dallas Cowboy star Emmitt Smith was the first athlete to take home the mirror ball trophy. Smith was a fan favorite and with coaching from pro Cheryl Burke, the NFL star proved that football players can cha-cha too.
Joey Fatone, Season 4
The former member of 'N Sync danced with pro Kym Johson and placed second overall back in 2007. (Fatone lost out to Olympian Apollo Ohno, who is also competing on season 15). Fatone has kept up his dancing skills on "DWTS: Live in Las Vegas."
Apolo Anton Ohno, Season 4
The former U.S. Olympic speed skater and eight-time medalist won season 4 with pro partner Julianne Hough in 2007. Ohno's technique and enthusiasm scored him major points with judges, who gave the Olympian a perfect 30 early on in the competition. His hip-hop inspired freestyle dance was voted No. 7 of all-time best dances in 2011.
Helio Castroneves, Season 5
The Brazilian race car driver was the big winner on season 5, quickstepping his way to the finish line with pro partner Julianne Hough. The Indy 500 champion's fast feet and his high-octane performances endeared him to the judges and the fans.
Gilles Marini, Season 8
The French actor, best known for his sultry scenes in "Sex and the City: The Movie," was a finalist on the eighth season, narrowly losing out to Shawn Johnson. Marini was a front-runner and favorite of the judges throughout the season but fell short of the mirror ball trophy.
Viewer's Choice: All-Star
For the first time in "Dancing" history, the 13th contestant will be voted on by fans online. Fashion commentator Carson Kressley (Season 13), singer Sabrina Bryan (Season 5), Disney Channel star Kyle Massey (Season 11) are vying for votes to score the coveted 13th spot in the competition. The winner won't be announced until Aug. 27. Watch "Good Morning America" Monday to see these stars live!