Anna Kournikova is in — and trainers Jillian Michaels, Brett Hoebel and Cara Castronuova are out as part of a massive refresh for the 12th season of NBC's hit weight loss series, "The Biggest Loser."

Michaels' departure was already in the cards — she made the announcement back in December that she was looking forward to pursuing other projects — but the departures of Hoebel and Castronuova are certainly unexpected. The two joined the show for the current season and were predicted to remain part of the core training team. 

As for Kournikova, executive producer Todd Lubin told New York Magazine that her presence is all part of a new direction the show will pursue. "[The show] is getting slightly away from just the tape measure, and getting into overall well-being and health," he said. "That's where 'Loser' needs to go."

Though hundreds of trainers were interviewed, Lubins says that Kournikova's greatest strength was that she has already guest-starred on the program with a tennis-themed workout. In fact, the group was so impressed with her performance that a spin-off featuring the 29-year-old was briefly considered. 

"She grew up with very little in Moscow, pounding tennis balls every day when she was 5," Lubin told the magazine. "That's the drive she's bringing to the show."

Season 11 of "Biggest Loser," which focused on couples, concluded last night with a pair of sisters — Hannah Curlee and Olivia Ward — competing for the top prize. Curlee dropped 120 pounds, or 48.39 percent of her total body weight. To beat her, Ward had lose more than 126 pounds. When the moment came to get on the scale, it showed a drop of 129 pounds.

“I think this time, for me, I really worked from the inside out,” Ward told "Today" show host Matt Lauer after the win. “I realized that weight loss happens in the mind and inside first. And if you’re faithful, then with the exercise and then diet — that part is science — the body will follow. For me (before), I just thought I had to grind my body into the ground with exercise and diet without really thinking about what was going on on the inside.”

Check out video of Ward's big win below:

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

Anna Kournikova joins 'The Biggest Loser'
Tennis star will whip contestants into shape during the upcoming 12th season.