On the April 21 airing of radio program, 'Cultwo Show,' Yesung appeared and made a promise to fans that he will fulfill if his first solo album takes first place.

He said, "I will reveal my abs.  I will wear something with a zipper, go on the program, and open it to show my torso."

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Regarding his first solo album, he said, "I'm a 12-year singer, but my first solo album came out.  It's a precious album I had prepared for four to five years.  I ask for a lot of love."

He added, "I was discharged from the military last year, so there was a hiatus of about three years.  A lot of outstanding juniors like VIXX (who was also on the show) came out, so I am engaged [in promotions] with the heart of a rookie."

If you wanna see Yesung's abs, you better get to it!