The show is to return in September.
"I'm so excited to be a part of 'The Biggest Loser' team; I've always been a fan of the show," Kournikova said in a statement. "As a former professional tennis player and certified trainer, this is a wonderful opportunity for me to share my enthusiasm for staying fit across America's homes. I'm honored to join a program that embraces the values of a healthy lifestyle and is committed to fighting obesity. I look forward to the upcoming season and seeing the results we can achieve together."
"We couldn't be more excited about Anna joining 'The Biggest Loser' family," added Paul Telegdy, executive vice president of alternative programming and specials for NBC and Universal Media Studios. "She is a fierce competitor and an accomplished athlete, and we are confident that she will be a powerful motivator to contestants to get fit and healthy."