The performance was a collaboration between vocal powerhouses Fly to the Sky and Lim Chang Jung. They sang each other's hit songs; while Lim Chang Jung sang "Even Though My Heart Hurts," Fly to the Sky took on the veteran singer's old hit "You're Like Me." Afterwards, the two sang the songs "Then Again," "Missing You," and, "One Shot of Soju" together.
During their performance of "Then Again," however, Hwanhee appeared to struggle with his part of the song. In the video shown above around the 2:06 mark, Hwanhee begins to sing to the climax, then pauses awkwardly for a moment before Lim Chang Jung swoops into the rescue.
Brian picks up the baton from there, but Hwanhee and Lim Chang Jung share a cute moment of smiles over Hwanhee's small mistake. While some believe that Hwanhee may have forgotten the lyrics, other believe it's more likely that his voice was worn out due to his recent concert activities.
Netizens sympathized with Hwanhee, saying, "Brian and Hwanhee's vocal conditions are bad TT. Because they had a continuous, two-day concert, they haven't had a chance to rest their voices; of course they would sound off," and, "So nice, Fly to the Sky. I prefer the singers of my generation rather than this one. Fly to the Sky, Wheesung, Gummy, Big Mama, Park Hyo Shin, Shinhwa--I miss the days when these kind of singers came out TT."