Hwang, who was a contestant on 'Korea's Got Talent 2' and 'Star King', is now known as "Little Psy" in his country.
He said he met Psy for the first time during the filming of the video.
"When I met Psy, he told me 'You really rocked when I saw you on television. Show me what you got today!' So I danced just like I did in the music video, then he said 'You are really awesome and have good talent.' It made me feel great," he said.
South Korea's second biggest electronics company LG recently made him a brand ambassador, appearing in a commercial that was shot in Hollywood.
Despite all the attention, Hwang said he doesn't tire of it.
"People ask me if I'm tired of being on television too frequently, but I never get tired. I will just dance with joy and just go crazy with it," the energetic seven-year-old said.
Hwang's mother said she discovered her son's love for dancing when he was just three months old. She said he used to stop crying and start moving his body whenever she played some music.
Recently, Hwang started taking professional lessons at a vocal and dance academy in Gwangju, 295km (183 miles) south of Seoul, where K-pop boy band Big Bang's Seungri and girl group Kara's Goo Ha-ra received training.
Hwang's dance instructor said the little boy has huge potential.
"Personally, I think Min-woo's dancing skills are excellent. He has great potential for the future. Despite he is just a little boy, he is full of energy. I think he can be a multi-talented entertainer who can show off many other talents if he gets more training," said Kim Dong-woo.