For years, Bob Harper and Jillian Michaels appeared to have great chemistry onscreen while filming "The Biggest Loser" together. But a new docuseries about the NBC weight-loss competition has fans wondering if the dynamic duo actually got along in real life.

Michaels, 51, alongside Bob Harper, 60, was one of the personal trainers on the NBC reality show, which aired from 2004 to 2016, following obese people as they attempted to lose weight as quickly as possible using only diet and exercise for a $250,000 cash prize.