K-pop star Kim Jaejoong of JYJ claimed that he had contracted coronavirus (COVID-19). It was later revealed that it was an April Fools' joke—and it did not go over well.

Kim posted via Instagram on Wednesday (April 1) that he tested positive for COVID-19. "I have been infected with COVID-19," he wrote. "It is a result of my negligence, disregarding the cautionary words of the government and my friends."

Hours later, he deleted the original post and issued an apology after backlash from fans ensued.

"This prank was too much to be considered a simple April Fools’ Day joke, but many people expressed their worry for me during that short period of time," he wrote, per The New York Times.

"It was not right. I know that," the 34-year-old added, per BBC. "I just wanted to deliver a message that we should all be aware of the risk to minimize the number of victims."

"So, I think we all need to be alert," he continued. "I just wanted to tell the people who don't care about the virus: 'Please listen up, people. Don't get sick.'"

See the post, below.