Whose singing career got the biggest boost from PSY's 'Gangnam Style'?  Undoubtedly, it is the 'sexy lady' who made an appearance in the 'Gangnam Style' music video, 4Minute's HyunA. As many as 1.5 billion people worldwide have seen, through Youtube, the girl who dazzles PSY with her sensual 'horse dance.'

But what about the female lead in the music video for 'Gentleman,' PSY's latest single that is now hitting global music charts? It is Brown Eyed Girls lead star Ga In. Within 17 hours of the music video's release, 'Gentleman' has received over 10 million views. PSY first made the music video public at his solo concert, 'Happening,' creating a worldwide sensation. It is undeniable that the female singer most likely to benefit from this midst of this sensation is none other than Ga In.

If this is so, why did PSY's agency, YG Entertainment, not choose the new 'PSY Girl' from within their own family, such as 2NE1, Lee Hi, Gummy, a new girl group, or the many other female members signed with the agency? Why did they go outside the YG family for both HyunA and Ga In? The head of YG Entertainment, Yang Hyun Suk, despite strong internal opposition, had pushed to have HyunA as the female lead for 'Gangnam Style.' Subsequently, he did the same for Ga In for 'Gentleman.'

Such behavior was very atypical of the CEO, who is particularly well known for keeping within the YG family. In regards to this matter, Lee Kyung Hwee director of OSEN gave some background knowledge.

"Within YG, there were many sides who wanted to pick between 2NE1 or a new girl group as the female lead for PSY's new music video," Lee explained. "However, Mr. Yang concluded that as with 'Gangam Style,' the candidate had to be someone who first and foremost fit the style of the music video, and Ga In was decided to be the most fitting."

After PSY was signed with YG, Yang fully backed the production of PSY's first album, which included 'Gangnam Style.' Yang put in a large scale investment utilizing global social media such as Youtube and iTunes, all leading up to his share in the song's unprecedented myth-like success.  According to high-ranking YG officials, Yang had been adamant even for 'Gangnam Style', demonstrating his strong influence over the casting with just a few words: "HyunA is the one."

In the end, Mr. Yang's policy in choosing the female leads for PSY's music videos has been consistent: regardless of agency affiliations, YG or not, he will choose the female singer who most suits the concept of the music video.

The music video for 'Gentleman' deals with men who call themselves gentlemen and their pranks that - if you're Korean - many people probably came across in childhood. The video shows crude, mature-only humor, and many critics have described it as PSY's challenge of Korean-style B-grade humor.

HyunA's comedic 'horse dance' in 'Gangnam Style' stole mens' hearts, and 'Gentleman' shows PSY openly running his hands over Ga In's body.