INTERNATIONAL NEWS - Jonghyun, full name Kim Jong-hyun, was one of the five members of Shinee, who have had a string of number one hits in their home country.
The Korean Herald said he was 28 years old. He was taken to hospital after being found unconscious in an apartment in Seoul, according to reports.
Police told the BBC Korean Service that suicide will be investigated as a possibility.
South Korean news agency Yonhap reported that emergency services were alerted by the singer's sister, and that he was later pronounced dead at hospital. Jonghyun shot to fame when the band was formed by K-Pop hit factory SM Entertainment in 2008.
