The unexpected passing of Moonbin, a member of the K-pop boy group ASTRO, has left his longtime friends and colleagues in deep sorrow.

Moonbin was found lifeless at his residence in Gangnam-gu, Seoul, on April 19 (KST). The police are investigating the exact cause of death, suspecting that he may have made a drastic decision.

Fantagio, Moonbin's agency, expressed their grief, stating, "Moonbin has suddenly left us and become a star in the sky. ASTRO members, fellow Fantagio artists, and staff are all deeply mourning his loss with great sadness and shock."

Moonbin's funeral procession took place on April 22 in a private ceremony, respecting the wishes of his family.

Close friends of Moonbin from his childhood, including SinB from the girl group BVG, have followed his social media account in his memory. SinB and Moonbin were same-age friends who grew up together in Cheongju, learning to dance alongside each other.

Following Moonbin's passing, Seungkwan from the boy group SEVENTEEN also added Moonbin's account to his following list. Previously, Seungkwan only followed official SEVENTEEN accounts and its members.

Actress Moon Gayoung shared memories of her friendship with Moonbin, which began when they worked together as child models. On April 22, she posted a photo from their past and wrote, "The moments from our beginning until you grew taller than me are all still vivid."

Other stars who worked with Moonbin in the past, such as Jung Chanwoo from iKON and Chanhee from SF9, also expressed their heartache over his passing.

Actress Kim Bokyung, who co-starred with Moonbin in the 2019 JTBC drama "At Eighteen," conveyed her farewell message, promising to remember the actor's work and expressing gratitude for their time together.

Moonbin's sister, Moonsua from girl group Billie, and her close friend Ro Jeongeui also paid tribute to the late star. Ro Jeongeui has maintained a close friendship with Moonsua since childhood.

Moonbin first gained attention in 2006 when he appeared in the music video for TVXQ's "Balloons" as a young version of the group. He made his official acting debut in 2009 with the KBS 2TV drama "Boys Over Flowers." In 2016, he debuted as a member of the boy group ASTRO and was active until his passing.