At around 10.37pm on the night of your Christmas party this December you are going to find yourself on the dance floor, half cut, moving messily to music that's one part generic R&B, one part a throbbing bass loop.

As you do so, you will be singing along to the lyrics, "Hey Sexy Lady". And you will be drunkenly pretending to ride a horse while you do it. At 10.38pm you will look around you and see that everybody else is doing exactly the same. That is the moment at which Korean music – or K-Pop as it i known – will have gone fully mainstream.

In fact, it already has gone mainstream if you are still in school. This evening a slightly pudgy Korean singer called Park Jae Sung (aka Psy) will probably become the first ever Korean singer to top the British charts. His single Gangnam Style – powered by its English-language soundbites and insane galloping-horse dance stance – is already YouTube's most liked video ever. Everyone from Robbie Williams to American rapper T-Pain have tweeted their approval, and marching bands all over the United States have been uploading their own Gangnam Style dance routines. The single may be the Macarena of K-Pop but its success suggests Korean music (from south of the 38th parallel, of course) has come of age.

If you have any teenage daughters it's possible you'll have been feeling its wash for the last couple of years. Around the country there are bedrooms full of pictures of young, pretty Asian boys. In my own house the names of SHINee, Super Junior and Beast have been part of the daily conversation with my kids for ages.

Language apart, it is difficult at first listen to hear what differentiates K-Pop from Western pop. Its mix of club-friendly beats and boy band histrionics sounds familiar enough. But to its fans it's the sliver of difference that's important. "It's not always all about partying," says 10-year-old Elizabeth Jamieson (most definitely a relation). "The music's more soulful," adds her friend Hannah Hiney, 14.

"I suspect part of K-Pop's appeal in the West is that it's a bit like Goths once were – a way of being different in a group," argues Mark Russell, author of Pop Goes Korea, and a blogger on Korean culture at www.markjamesrussell.com. "You get to have this secret thing that you and your friends know and love and can bond over, but most of the mainstream doesn't get."

And that is a key part of the appeal of the genre. K-Pop is something fans have had to find for themselves. The internet and social media have been key to this. In South Korea, K-Pop bands appear in specially created dramas to promote the music (and the brand). These dramas have been uploaded online with fan translations. K-Pop allows a more involved sense of ownership for fans.

"The internet has broken down the old barriers and overthrown the old cultural gatekeepers," argues Russell. "For years, A&R execs at the big Western music labels told me that they were not interested in 'Korea's Britney Spears' or 'Japan's Backstreet Boys' or whatever, because Asian pop could not succeed in the West. Turns out those middle-aged, self-important executives did not know their customers."

Social media also connects and consolidates fans of niche cultures. As a result, they begin to wield some power. At last year's MTV European Music Awards the winner of the best worldwide act award was Korean group Bigbang, who attracted 58 million votes. iTunes started selling K-Pop to European fans as early as 2010 and, at the end of last year, Google launched a standalone K-Pop YouTube channel.

The bands themselves have been dipping their toes in the European market with the likes of Super Junior and Girls' Generation staging shows in Paris, Los Angeles and New York, while SHINee played London last year. "There was a K-Pop flash mob in Stockholm last week," adds Russell, "and I believe the city is getting a K-Pop-themed bar. I've heard K-Pop songs in real Catalan restaurants at the edges of Barcelona, far from any tourists. I've gotten emails from Korean soap-opera fans in Egypt. And now K-Pop appears to be gaining popularity in South America too."

In short, the future is Asian. Neigh doubt.

K-POP: WHAT YOU NEED TO KNOW ABOUT THE MUSIC

So what is Gangnam Style about?

Apparently, after much deciphering of lyrics, it turns out the song actually has a point to make. Gangnam is a rather upmarket area of Seoul – think Chelsea mixed with Hoxton – and the song is sending up the area's phoney, highfaluting poseurs.

How do I do the Gangnam Style dance?

Easy. First pretend to ride a horse in a rather limp-wristed way, then swirl your imaginary lasso around your head, next put those hands on your hips and lastly flip those feet. One watch of the YouTube video should make you an aficionado in no time.

Who's the funny fat guy in the video?

That's Psy – he's the 35-year-old Korean writer and performer of Gangnam style. A rapper by trade, he studied at Boston University and has his tongue firmly in his cheek with this satire of K-Pop. He's famous worldwide now, has appeared on The Ellen DeGeneres Show and Saturday Night Live and even taught Britney Spears how to dance Gangnam-style.

What does the world think of it all?

There have been Gangnam Style flashmobs across the world – including one at the University of Aberdeen and another that filled Times Square in New York. Other locations include the Hotel Indonesia in Jakarta, a food court in Sweden, a shopping mall in Paraguay and during the 40th anniversary of the declaration of Martial Law in the Philippines.

What's the reaction been like in the world of showbiz?

Here's a taste of celeb thoughts on Gangnam Style from the Twittersphere – Robbie Williams: "Try watching this and not smiling I dare you"; Katy Perry: "Help! I'm in a Gangnam Style K-hole"; Tom Cruise: "Think Psy would make a good future co-star"; James Cordon: "I am so into Gangnam Style it's insane!"

And are our more serious commentators saying anything?

Why, yes. Here's what some of the biggest papers in the world are making of Gangnam Style...

De Morgen, Belgium: "The invisible horse in this silly dance is like a metaphor that represents man's desire to be rich."

People's Daily, China: "A divine melody."

Stern, Germany: "Psy looks like Kim Jong-Il."

Dagens Nyheter, Sweden: "A worldwide hit with a well-produced dance floor beat and an irresistible, inescapable refrain."

K-POP: WHAT YOU NEED TO KNOW ABOUT THE STYLE

WALK into a shop. Now look for the loudest, brightest print, the edgiest slogan T-shirt or – if you're male – a sharp-cut blazer. This is the first step to dressing, K-Pop style.

The look of these Korean artists, including Psy and girl bands 2NE1, Kara and Girls' Generation, is about standing out from the crowd.

Think printed trousers so garish they run the risk of inducing a migraine, neon mini skirts with stripes and massive oversized unicorn images. The style matches the music: unashamedly loud and proud.

Style expert Wyelin Chiu, whose blog Eiffel In Seoul attracts thousands of visitors every day, believes Asian pop culture and style is making an impact in the West more than ever because of the K-pop phenomenon.

"The artists are definitely making an impact not only in Asia but also in America and Europe," said the 20-year-old, from Singapore, who began blogging three years ago because she felt there were no commentators discussing what Asian celebrities wear.

"There are different styles in the K-Pop fashion," Chiu added.

"With the ladies, they can go extremely feminine, a little edgy, or very loud, like 2NE1. The males are usually dapper in blazers and suits or in loud prints."

Chiu says the fashion is as addictive as the music. "Everything about K-Pop is incredibly catchy, which is why everyone is hooked quickly."

It appears K-Pop is helping Asian pop culture to filter through into mainstream fashion.

The four members of 2NE1 and Chinese actress Yao Chen both attended Vera Wang's spring/summer 2013 show during New York Fashion Week, while Korean actress Jeon Do Yeon attended Burberry's spring/summer 2013 show during London Fashion Week. Fashion designer Jeremy Scott even designed costumes for 2NE1's concert tours.

Chiu said: "Designers are starting to realise that there is a huge market in Asia."