NBC has revealed more details about the upcoming season of The Biggest Loser. As previously reported, soap star Allison Sweeney will replace Caroline Rhea as host -- but that's not the only casting news that will have fans buzzing. Trainer Jillian Michaels, who was replaced by Kim Lyons last season, will return to the show in a surprising new twist. She will be joining Kim and Bob Harper.

In other casting news, a set of twins will be competing for the first time. The show will also welcome its oldest contestant ever (age 62).

The new season will premiere on Tuesday, September 11 . It is being called the Back to the Basics season because the contestants will be competing at a new campus location that doesn't have the luxuries of the ranch. This should be interesting!

On Tuesday, Sept. 4, NBC will air a Biggest Loser Where Are They Now? special, featuring some of our favorite "losers" from the first three seasons of the show.