Pop star Psy still can't believe how successful his Gangnam Style hit became five years after he first dropped the catchy summer tune.

The song, which came with its own dance routine, was released on 15 July, 2012, and quickly turned the South Korean rapper into an international superstar, while his video became the first to hit one billion views on YouTube.

Psy tells Billboard he had no great expectations for his song as he released it and admits, "I didn’t expect anything global".

"I just did what I’ve done before," he adds. "I was a Korean singer and whenever I released an album, the purpose of it was just to make good songs in Korean, and hopefully to make a hit song that people in Korea could enjoy. That was everything.

"Before Gangnam Style, I had already done music and been a singer in Korea for more than a decade, since 2001. Similarly to other previous singles, I made energetic music and funny music along with funny dances, funny videos, and funny lyrics. I honestly didn’t mean anything that much (sic)."

Psy didn't realise he had an international hit on his hands until he received a phone call from Justin Bieber's manager Scooter Braun: "He was really interested in the song and video, and me," Psy recalls. "He thought he could make it huge in the U.S. As soon as I got the call, I Googled him. When I found out who he was, I was so shocked and felt that maybe the song could become something. That was the first moment I thought it was different."

Unfortunately, the Gangnam Style video wasn't able to hold its position as the most-viewed promo on YouTube for the song's fifth anniversary - it was dethroned by Wiz Khalifa and Charlie Puth's See You Again earlier this month (Jul17). But Psy isn't complaining because his success has turned him into the unlikely poster child for Korea's K-Pop movement.

"In Korea, there are so many muscular, handsome, pretty K-poppers and I’m kind of chubby, honestly," he adds. "Personally, I felt a little bit guilty representing my country’s music. Right now if somebody is going to do a better job than me from now on, he or she has to be less chubbier than me (sic)."