I could have put this clip in my earlier post about Park Hyo Shin, but I hadn't watched it at the time, thinking it was the performance -- not one of his best, to my mind -- from his concert DVD. It's not; apparently it's from a TV appearance the beginning of his career.
One commenter here claims that Park was 17 in this clip. I can't find a date for it, but it's possible. (P.S. Or maybe not: According to Wikipedia he was born in 1981, and his first album was released in 2000, when he was 18 or 19. But he was still probably a teenager at the time of this performance.) If so, he's just that much more impressive. His English diction is rough (another commenter said when Park sings in English, he sounds like he has a mouthful of marbles), but that's more than made up for by the fluency and emotional intensity of the performance.