Grueling gym routines, restrictive diets, and no dating: K-pop stars tell us about the dark side of

BTS fans, who are in their millions, call themselves the "Army" and once flooded a Korean restaurant with one-star Yelp reviews after its owner said another band was better.

Other hardcore K-pop fans also pool their money together to buy presents — including billboard ads in Times Square — for their idols in a practice based on the Korean word "jeogon," which means "tribute to the king."

But behind the scenes, the reality is different.

Insider spoke to members of Great Guys, an up-and-coming boyband consisting of nine men in their 20s, after their performance at the Korea Drama Festival in Jinju in early October.