NBC's 'The Biggest Loser' is undergoing some major changes, and the latest addition to the training staff is Justin Bieber's personal trainer Dolvett Quince.

According to Us Weekly, Quince will join 'BL' vet Bob Harper and tennis pro Anna Kournikova as trainers for the fitness show's twelfth season, which is set to begin production this week.

"I couldn't be more excited about joining 'The Biggest Lose as their newest trainer," Quince, who has also worked with Janet Jackson, told Us. "This amazing opportunity allows me to use my expertise to change lives one rep at a time, and encourage contestants -- and viewers -- to find strength beyond muscle."