Korean pop phenomenon Psy was at Harvard University's Memorial Church to take part in a conversation about "Gangnam Style" and the role digital media played in turning it into a global hit and Psy into a global superstar.

He was greeted by screaming Harvard University students outside the church, which is dedicated to the memory of those who lost their lives in World War I.

"Gangnam Style" was viewed more than 1.5 billion times on YouTube, making it the most viewed video ever on the site.

It had people young and old around the world doing the trademark "Gangnam Style" dance and spawned lots of viewers' own versions.

But Psy thinks his huge YouTube hit was probably a one-off.

"Gangnam style was not normal. Gangnam was not standard ... that was an accident and accidents don't happen often," he was quoted as saying by the Associated Press.

"I gotta be humble, I gotta be humble, I know I gotta be humble because this does not happen to everybody — especially for Asian artists."

Reflecting on why he managed to make it big in the US, where so many other artists have failed, he admitted he never thought it would happen for him "because, as you see, I have a very special body shape".

He thinks it may just be down to the fun he has with music.

"There should be a specific reason why people chose me," Psy said. "They didn't choose me because I'm handsome, they didn't choose me because I'm muscular ... the reason why they chose me (is) because I have fun with the music, with the dance, with the video."