A blown-up poster of the company founder Park Jin-young is plastered on the building’s facade, making it impossible to miss. The excited faces of a group of young people standing outside it suggest something is going on.

“Why did Jackson (of GOT7) come here? I thought he didn’t have anything on his schedule today,” said one person in a group of 20-something Koreans who were discussing the matter among themselves.

“I heard reporters were angry because the photos were on the internet before they distributed it.

“Well, s---- them,” said another group.

The flock of excited fans gathered in a doughnut shop across the building -- waiting all day for their stars to show up and exchanging information in the meantime. They offer a peek at the lengths to which dedicated fans will go in order to see their stars.

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K-pop fans gather outside the JYP headquarter in Cheongdam-dong, southern Seoul, Wednesday. (The Korea Herald/Park Hyun-koo)

The five-member boyband H.O.T. debuted in 1996, ushering in the age of K-pop idols, a blanket term that refers to a musical group of young and attractive males and females produced by mainstream talent agencies for the mass public.

Groups of fans soon formed and they became known for their devotion to their heroes, true to the original definition of the word “idol.”

“I know GOT7 doesn’t have anything on their schedule today so they’re not likely to come here today. But I came here anyway in case I might get a glimpse,” said a Chinese tourist who identified herself as a fan of the boy band.

She and a group of young Japanese women had been waiting there for hours, occasionally glancing out of the window for any sign of stars pulling up.

On the other side of the doughnut shop was a seemingly disinterested group, who nevertheless kept a keen eye on everything that went on outside the window.

This was clearly not their first day there.

Then, the fans inside the shop rushed outside to look at a group of men stepping out of the JYP building. Their excitement bore no fruit as the men quickly stepped into a van and drove away, but the fans were unfazed and seemed determined to keep waiting.

While other agencies also have fans staking out in front of their headquarters, not many have gained a reputation like the doughnut shop outside the JYP headquarters.

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“I think it’s because our fans enjoy K-pop content at places like SMTown Coex Artium, which offer concerts and fan events,” said an official from S.M. Entertainment.

But the other agencies by no means have a shortage of diehard fans.

Fans of S.M. Entertainment superstars have a reputation bordering on notoriety for their devotion.

“EXO concerts are always sold out, so I would buy the tickets from a scalper for 200,000 won ($174) to 250,000 won,” said Kim Hyun-soo, 14, from Yongin, Gyeonggi Province, who is an avid fan of EXO’s Chen. The ticket price is normally around 100,000 won ($87).

“We also buy expensive custom-made glow-in-the-dark sticks (used for cheering the singers on), which have Bluetooth connection so they all simultaneously change color (during the concert),” he said.

Kim said he spent about 1 million won buying tickets for all six concerts of the group’s last tour, which is substantial considering he is still living on an allowance.

Besides going to concerts and buying albums, fans find other ways to show their devotion.

Earlier this month, fans of the boy band BtoB collected money to post an advertisement on two buses in Seoul, in celebration of the birthdays of members Hyunsik and Peniel.

Some fans go beyond pampering their idols.

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Last September, Jackson of GOT7 was injured in a traffic accident in China. This occurred while he was trying to escape fanatic fans, known as “sasaeng” fans, referring to those who invade the privacy of their stars.

Such fans of K-pop stars have been reported to break into stars’ homes, steal their personal belongings or even install a CCTV camera to keep an eye on their every move. Boy band JYJ, which previously came under fire for cursing at such fans, claimed that some of the fans tried to kiss them while they were sleeping or intentionally bumped into their cars with a taxi just to see them.

However, many fans appear content just to catch a glimpse, shout a few friendly words and get an autograph.

“They come almost every day to see the stars,” said a passer-by near the JYP headquarters where fans were staking out. “It’s almost cute, how determined they are.”