K-pop star Moonbin, a member of the boy band Astro, has died, his music label and South Korean police said Thursday, prompting an outpouring of grief from fans.

The 25-year-old singer was found dead at his home in southern Seoul late Wednesday, a spokesperson for the National Police Agency told AFP, adding that there was no evidence of foul play.

Moonbin's label Fantagio Music also released a statement on Thursday confirming his death but without disclosing the cause.

"On April 19, Astro member Moon Bin unexpectedly left our world and became a star in the sky," it said on Twitter.

It asked that people "refrain from speculative and malicious reports" so that his family can pay their respects and honor him in peace.

The label's announcement prompted thousands of comments from grieving fans, many expressing disbelief.

"Rest in peace, Moonbin. I hope the stars and the moon treat you well. I hope they give you all the comfort and love," one wrote on Twitter.

"I can't focus on work now. This really hurts," wrote another.

Moon Bin -- who performed as Moonbin -- was a member of the group Astro and also performed with a sub-group called Moonbin & Sanha.

He joined Fantagio's trainee program at an early age and was an actor and child model before debuting with Astro in February 2016.

Prior to his passing, Moonbin & Sanha had been set to perform at the upcoming Dream Concert -- one of the largest K-pop joint concerts in South Korea -- in May.

The group had also been in the middle of their Diffusion Fan Con Tour across Asia, and had launched an official fan community page on Weverse -- the global fandom platform from K-pop megastars BTS's agency HYBE -- on Sunday.

"While no passing from any artist is ever to be expected, Moonbin's untimely passing was all the more shocking given how active the young star was, even the week of his death," Jeff Benjamin, Billboard's K-pop columnist, told AFP.

"No one around him saw this coming, but what we can keep is his undeniable smile," he added.

"I've seen its brightness compared to the Cheshire Cat from 'Alice and Wonderland', and the wonderful music and performances he gave us."