SEOUL (AFP) - A young South Korean construction worker has become an international singing star after more than 10 million YouTube users watched his powerful performance on a local TV talent show. Nobody expected such a deep and strong baritone voice from a nervous 21-year-old Choi Sung-Bong when he first appeared dressed in jeans and trainers on Koreas Got Talent in early June. After telling the audience that he doesnt sing well, Choi performed a sensational Nella Fantasia that reduced the audience and the judges to tears. Chois success compared by some to Britains Susan Boyle is all the more remarkable given his tough early life. I was left in an orphanage when I was three...I ran away when I was five due to abuse, he said in comments during a total of three TV appearances. Choi said he supported himself selling chewing gum or energy drinks in the street and slept on stairways or in public bathrooms for about 10 years. After skipping elementary and middle school, he entered an arts high school at the age of 16 and graduated in 2009. Choi had to work during his high school years given his lack of financial support, said a spokeswoman for CJ E&M, the channel that airs the talent show.