Jin of BTS performs during his fan showcase "Jin 'Happy' Special Stage," held at Jangchung Arena, Seoul, Sunday. (Big Hit Music)

Jin mesmerized fans with his wide musical spectrum and vibrant energy at the fan showcase “Jin ‘Happy’ Special Stage” on Sunday.

Held Saturday and Sunday, the showcase marked the first live performance of songs from Jin's first solo album "Happy." Over two days, Jangchung Arena in Seoul was packed with approximately 3,800 fans.

As Jin appeared on stage by parting the red curtains, the arena erupted into thunderous cheers. "Two days ago, my album was released. I wanted to properly introduce my first solo album, 'Happy,' to Army," said Jin.

The first stage, divided into two sections, was designed with contrasting themes: an office on one side and a road through the vast wilderness on the other. Jin performed the main track "Running Wild," transitioning from the confined office space to a liberating drive through the open landscape, symbolizing a journey toward freedom.

Introducing the album in a later segment, Jin said, "When I think of the word 'Happy,' things like BTS, sleep, Army, games and rest come to mind. Among them, what makes me happiest is Army. I created this album with the hope of bringing happiness to all of you."

He also revealed a behind-the-scenes story about the album's only duet track, "Heart on the Window," featuring Red Velvet's Wendy. "While I was considering potential collaborators for the duet, I happened to have a meal with an acquaintance, who turned out to have Wendy's phone number. I asked him to make a quick call, and asked Wendy to collaborate," Jin explained.

During the event, Jin answered a question from a fan about "I Will Come to You" which he wrote.

"Right after I entered the military, I really missed performing and Army so much. I wrote down my emotions at the time and those notes eventually became the lyrics for this song."

Later, the stage transformed into an alley on a rainy night and Jin reappeared in a brown jacket to perform the modern rock track "Falling," on which Japanese rock band One Ok Rock members Taka and Toru featured. As Jin sang "Heart on the Window," Wendy joined him on stage.

"Singing in front of Army feels like debuting all over again. Thank you for letting me be part of such a wonderful album," Wendy said before leaving the stage.

Returning to the stage in a soft white wool sweater, Jin performed the ballad "I Will Come to You" accompanied by a piano, captivating the audience with his emotional delivery. The atmosphere shifted dramatically with the powerful alternative rock track "Another Level."

Jin concluded the show with a medley of his solo tracks released before "Happy," such as "Super Tuna," "Moon" and "Astronaut."

"I thought happiness had an end, but there was more happiness waiting for me. I’m BTS Jin, thoroughly happy because of all of you," he said.