Who is the 'Biggest Loser'? Winner to be crowned Tuesday

UNDATED (NBC) -- It's live reality night on 7NBC.

"The Voice" will narrow its field from eight singer to the final four in a live broadcast, but before they take the stage "The Biggest Loser" will crown its 13th champion in a live season finale.

A weight loss journey that started months ago culminates tonight with one final weigh in.

Former professional wrestler Kim Nielsen of Roswell, Georgia is convinced it'll go her way.

"My competitive spirit doesn't turn off. I am going to be the one at the end of this with the

confetti coming down on my head," she says.

Single mom Conda Britt of Rockford, Michigan has been the season's polarizing force.

"Personalities clash, but I feel like, for the most part, I stayed true to who I was," Britt says.

She had the support of younger brother Jeremy, who literally had to hang on for more than three hours to earn a spot in tonight's final.

"This is one challenge I'm going to have to take from Conda because I'm definitely going to be the Biggest Loser," he predicts.

The scale will be the final judge.

Tonight's winner will take home $250,000.

Contestants who were sent home from the ranch are still in competition.

They're all vying for $100,000.