A chubby singer with slicked-back hair and a tacky suit from South Korea has become a global internet sensation after racking up 27m YouTube hits in less than a month.

Psy's Gangnam Style became a hit in his home country before spreading overseas, gaining celebrity followers including Robbie Williams and coverage in publications including the LA Times and Wall Street Journal.

Internet sensation Psy does not fit the stereotypical "pop idol" profile

The video features the unlikely pop star posing on a speedboat in a garish lifejacket, lying on the floor of a lift while a man in bermuda shorts gyrates above him and performing a trademark "horse-riding" dance, which has sparked dozens of imitation clips on YouTube and social networking websites.

The song has entered the Billboard Social 50 - a chart that ranks the most popular artists on YouTube, Facebook, Twitter, Vevo and Myspace - and Psy is preparing for a string of media appearances and a meeting with Justin Bieber's producer in the US.

Many scenes in Gangnam Style's wacky video defy logical explanation

In South Korea the song is seen as a humorous send-up of the country's bland K-Pop genre.

The title refers to the lavish lifestyles of residents of the Gangnam district in South Korea's capital, Seoul.

Psy, who has had little international success during a 10-year career, admits he has been taken aback by the song's success.

The hit YouTube clip sends up the typical male pop star image

He told the Wall Street Journal: "I didn’t expect it at all. Of course every time I write a song, I hope people like my music.

"But since I’ve been always a singer for the local market, it never occurred to me that people outside the country would listen to my music.

"I didn’t even have overseas fans. When I wrote the song, I had only one thing in mind — to create a fun song."