JYJ's Kim Junsu, who contributed songs to the soundtracks of several popular k-dramas, is taking a stand against cyber bullies.

Junsu, who sings on the OSTs of "Sungkyunkwan Scandal," "Rooftop Prince," "Empress Ki" and "Six Flying Dragons," is taking legal action against Internet users who posted malicious comments. He plans to sue the offenders for slander and spreading false information. It was not a decision he took impulsively or without warning those making the comments. In July 2015 he commented on Twitter that he was reaching the end of his patience.

"I used to brush them off, thinking, 'Maybe they'll come around if I do better,' but some of them have crossed the line and I realized that I should no longer ignore them."

According to his agency, C-JeS Entertainment, the news that Junsu was dating EXID's Hani increased the number of negative comments. Junsu and Hani revealed their relationship on January 1 after photos of them were published. The singers confirmed that they dated for six months. But the news was not received well by all online commenters.

"We found a few people who left malicious comments and groundless rumors online by tracking their Internet IDs," C-JeS said in a press release. "We are discussing whether to bring charges against the commenters through the prosecutor's office or work with the Cyber Bureau of the Gangnam Police Precinct."

According to the Korean media outlet Joongang Daily, this will be the first time that C-JeS Entertainment has taken action against malicious online comments, although they previously threatened to do so in defense of fellow JYJ member Kim Jae Joong.

And Kim Junsu is not the first k-celeb to take action against nasty comments. There has been an increase in the number of k-celeb defamation suits filed against netizens.

In November 2015, Loen Entertainment released a statement saying they were taking legal action on behalf of singer-actress IU.

"We sued those who spread false reports about IU and distributed altered images of her," the company said. "Before and after IU's comeback in October, many netizens were making personal attacks on IU by leaving malicious comments and spreading rumors online. We have continuously monitored the malicious comments and are using that as grounds to file a lawsuit. There will be absolutely no leniency granted. We will strongly retaliate and are considering pursuing criminal punishments."

IU previously sued anti-fans in 2013.

Junsu's actions may have been inspired by the success of the suits filed by his label mate actor Lee Jung Jae. In 2015, the agency also sued netizens on Lee's behalf, for leaving malicious comments about his romantic relationship with Lim Se Ryung, the eldest daughter of the chairman of Daesang Corporation. His agency filed charges against 50 malicious commenters.

As of January 8, 2016, ten netizens had been caught, prosecuted and fined. More cases were being processed.

In 2012 actress Song Hye Kyo sued 41 netizens who spread the rumor that she was being financially sponsored by a politican in exchange for sexual favors. She did not even know the politician. Twenty-one netizens were indicted and had to pay fines.

Other stars who have taken similar action include Lee Young Ae and Baek Ji Young.

Increasingly k-celebs and their agencies are choosing to prosecute rather than ignore career-damaging comments. On January 11, FNC Entertainment, which represents Jung Yong Hwa and Lee Hong Ki, also released a statement warning that they would prosecutre cyber bullying.