Billlie's Moon Sua shared a touching tribute to her late brother, ASTRO's Moonbin, on the second anniversary of his passing.

On April 19, Moon Sua took to social media to express her emotions ahead of the release of "Moon in the Dream", a tribute single honoring Moonbin.

💌 "I Sang for You for the First Time"

"Oppa, are you doing well?" she began. "For the first time, I sang a song thinking only of you."

The song Moon in the Dream will be released at 6 PM KST, featuring 22 artists including members of ASTRO and Billlie. It's described as a letter to Moonbin, waiting behind the door of the moon.

Sua revealed how emotional and delicate the process was:

"It was my first time singing for you, and that made me even more nervous, even more careful. I just wanted to do my best for you—this was the only way I could express how I feel."

🌙 "I'll Always Remember Us Like This"

Highlighting the lyric "I'll always remember us just like this," she wrote,

"That line felt like us. I thought a lot about which song to choose, but this one just felt right."

💞 "Forever, the Moon Siblings"

Closing her letter with love and longing, she said,

"When we meet again, carry me on your back and give me the biggest hug. Let's be together forever, Moon siblings. I'd choose to be your sister again in any life. I miss you so much. I love you."

[Photo Credit: Moon Sua's Instagram]