The Biggest Loser: Temptation Nation's live finale Monday night will feature a surprise twist with the potential to be a huge game-changer.

During last week's episode, Roberto Hernandez, a 36-year-old physical/health/driver's education teacher from Burbank, IL, and Stephen Kmet, a 43-year-old pharmaceutical sales recruiter from Hainesport, NJ, were declared the first two of three finalists.

At the beginning of tonight's final broadcast, either Stephen's wife, Jacky Kmet, a 42-year-old high school counselor from Hainesport, NJ, or Colby Wright, a 31-year-old car dealership salesman from K'Ville, GA, will be revealed as Season 17's third finalist competing for the ultimate $250,000 grand prize.

According to NBC, "the final three contestants will be surprised with a new twist that will raise the stakes even higher in the competition as Season 17 comes to an exciting close."

The new twist could "dramatically impact the competition."

Throughout the finale, the 16 contestants who opted to change their lives on the ranch this season will weigh-in one last time to show off how much weight they've lost and how far they've come -- not only physically, but also mentally and emotionally as well. One of the previously-eliminated players will win the $100,000 at-home prize.

The Biggest Loser's two-hour finale kicks off at 9PM ET/PT on NBC.