Osmond, DeLay in "Dancing With The Stars"

Sixteen celebrities from the worlds of entertainment, sports and politics will be kicking up their heels on the new season of "Dancing With the Stars."

The show's largest cast ever, announced Monday, features singers Mya, Macy Gray and Aaron Carter; actors Ashley Hamilton, Melissa Joan Hart and Debi Mazar; and models Joanna Krupa and Kathy Ireland. (Here's a look back at the casts of the previous eight seasons.)

Contestants also include reality stars Mark Dacascos and Kelly Osbourne; entertainer Donny Osmond; mixed martial artist Chuck Liddell; professional snowboarder Louie Vito; Olympic swimmer Natalie Coughlin; former Dallas Cowboys wide receiver Michael Irvin and former Republican Majority Leader Tom DeLay.

The contestants were announced on Monday's "Good Morning America" by DWTS host Tom Bergeron, who also unveiled a new competitive twist.

"In the middle of our season, over three weeks, we're going to have double eliminations," said Bergeron. "We'll lose about half of our cast within that period. It will be a ballroom bloodbath."

Samantha Harris returns as co-host, with the panel of judges including ballroom judge Len Goodman and dancer-choreographers Bruno Tonioli and Carrie Ann Inaba.

Two members of the upcoming cast are related to previous "Dancing With The Stars" competitors. Donny Osmond's sister Marie was in show in the fall of 2007 and Ashley Hamilton's father George was in one of the 2006 casts.

The show is sometimes seen as an opportunity to give new life to flagging careers or to rehabilitate tarnished images. While both Marie Osmond and Cloris Leachman of the fall 2008 season got some career boosts from their appearances; other did not fare as well. Actress Tatum O'Neal suffered from an early elimination, for example, and Britain's Heather Mills did little to win admirers in the wake of her bitter divorce from ex-Beatle Paul McCartney.

The ninth season of the hit ABC show premieres Sept. 21.