PSY, the rapper whose song Gangnam Style has taken the world by storm - currently number one in the UK, with more than 50 million views on YouTube, and that's not even the official video - has found a small way to say thank you to his home-grown fans.

gangnam style
PSY in action on stage in South Korea

The South Korean singer held a free concert for 80,000 in South Korea's capital of Seoul on Tuesday - with fans entering an online lottery to get a ticket.

WATCH PSY in action above - how many people did he get dancing?

Meanwhile, the inmates of Cebu Provincial Detention and Rehabilitation Center in the Philippines have also got in on the act.

The prison dance troupe, famous for performing to Michael Jackson's Thriller five years ago, have stepped up again for their own rendition of Gangnam Style. Watch them in action below...

Meanwhile, PSY has told how music bosses urged him to undergo cosmetic surgery to enhance his looks before he found fame.

The hitmaker admits he was horrified when label chiefs demanded he undergo a drastic image overhaul.

He recalls, "The agency heard my raps and were picturing a six-foot tall, sharp-looking, trendy guy. But the CEO opened our meeting with the statement, 'What are we going to do with this?' Staff said, 'How about we make him wear a cool mask?'

"Everyone was coming up with solutions to my 'looks problem'. They said, 'How about a bit of plastic surgery here and there?'

"The CEO's response to that was, 'Just a bit?' In the end they reached no conclusions and just walked out of the room."