Sept. 4, 2013 -- The choreography, costumes, and heated competition are all back for season 17 of "Dancing With the Stars," along with 12 new celebrities ready to take to the dance floor.

Actress Valerie Harper, "King of Queens" star Leah Remini, TV personality Jack Osbourne, former NFL star Keyshawn Johnson, and reality star Nicole "Snooki" Polizzi are among the contestants vying for the coveted mirrorball trophy this season.

Singer Christina Milan, "Glee" star Amber Riley, actress Elizabeth Berkley Lauren of "Saved by the Bell" fame, and comedian Bill Engvall, will also lace up their dancing shoes this season.

Disney star Corbin Bleu, Brant Daugherty of "Pretty Little Liars," and Bill Nye, who is best known as "The Science Guy," round out the dynamic lineup.

The entire 2013 celebrity cast was revealed live today on "Good Morning America" in New York City's Times Square. Hosts Tom Bergeron and Brooke Burke-Charvet kicked off the much-buzzed about announcement and also unveiled the celebrities' professional partners, including reigning season 16 pro champ Derek Hough and beloved veterans Cheryl Burke, Mark Ballas, Karina Smirnoff, Tony Dovolani and Val Chmerkovskiy and more.

Which cast member has seven tattoos? Click here to find out fun facts about the season 17 cast.

The new season kicks off with a two-hour premiere on Monday, Sept. 16 at 8 p.m. ET/7 p.m. CT on ABC. For the first season ever, the hit show will combine the performance and results show into one two-hour program on Monday nights. The couple with the lowest scores from the judges that night combined with the public votes from the previous week's performance will be eliminated.

Which couple are you most excited to see hit the dance floor this season? Tell us what you think in the comments.

Meet the Season 17 Cast

Meet the pro partners and see the season 17 pairings!

Valerie Harper

Actress Valerie Harper, beloved for her role as Rhoda Morgenstern on the classic TV sitcom "The Mary Tyler Moore Show," will give "Dancing" a whirl this season. Diagnosed with terminal brain cancer earlier this year, Harper, 74, has exceeded doctors' expectations and continues to be optimistic about her prognosis.

"The brain scans that you get every two months are looking better and better and better," Harper said today on "GMA." "My doctors and neurologists …. they are just delighted that I'm moving in the right direction. As my husband said, 'Let's just buy time, Val."

Nicole "Snooki" Polizzi

Reality TV star Nicole "Snooki" Polizzi, who made a name for herself on MTV's "Jersey Shore," brings her unabashed big personality to the ballroom this season. The new mom, who showed off her recent weight-loss, is also a best-selling author and stars in her own reality show, "Snooki & JWoww."

Keyshawn Johnson

Former NFL Super Bowl champion and three-time Pro Bowl wide receiver, Keyshawn Johnson will tackle the dance floor this season. Johnson played for the New York Jets, Tampa Bay Buccaneers, Dallas Cowboys and Carolina Panthers during his career, and went on to join ESPN as an NFL analyst and personality.

Leah Remini

Actress Leah Remini, who has starred for nine seasons on the hit comedy, "The King of Queens," has been a television fixture since age 18 with memorable roles on sitcoms like "NYPD Blue," "Friends," "Saved by the Bell," and now "Dancing With The Stars."

Jack Osbourne

TV personality Jack Osbourne, the 27-year-old son of rock legend Ozzy Osbourne and wife Sharon, brings his spunk to the dance floor for season 17. Osbourne, who most recently hosted the SyFy series "Haunted Highway," opened up about his shocking diagnosis of multiple sclerosis last year.

Christina Milian

No stranger to the stage, singer Christina Milian will compete on the dance floor this season. Milian, who is currently recording her fourth album, broke out in the music world with her hit "AM to PM" and was recently the social media correspondent for "The Voice."

Amber Riley

Amber Riley turns heads with her killer vocals as Mercedes on the hit musical comedy, "Glee," and will now be performing on the "DWTS" dance floor. Riley is currently working on her debut solo album. Pro Partner: Derek Hough. Riley will dance with reigning season 16 pro champ Derek Hough, who returns for his 12th season.

Bill Nye

TV personality Bill Nye, known to kids simply as his character "The Science Guy," will explore the world of dancing this season.

"It's all physics; it's all the study of motion," Nye said today about applying his knowledge on the dance floor. "I'm feeling great."

The mechanical engineer has a passion for science and is writing a new children's book about energy.

Elizabeth Berkley Lauren Actress Elizabeth Berkley Lauren, who began her TV career as Jessie on the hit sitcom, "Saved by the Bell," will take her turn on the dance floor this season. The actress is also a New York Times bestselling author for her book "Ask Elizabeth," and a new mom.

Corbin Bleu

Disney star Corbin Bleu, best known for his role as Chad in the "High School Musical" franchise and who has also starred on Broadway, is lacing up his dancing shoes this season.

Brant Daugherty

Millions of "Pretty Little Liars" fans know Brant Daugherty as Noel on the hit ABC Family show and now the actor will give "Dancing" a whirl.

Bill Engvall

Comedian Bill Engvall, best known as a member of the Blue Collar Comedy comedy troupe and for his "Here's Your Sign" bit, will bring his humor to the ballroom this season.

Meet the pro partners and see the season 17 pairings!

Watch the two-hour premiere on Monday, Sept. 16 at 8 p.m. ET/7 p.m. CT on ABC.