There can be few people left in the world who have not heard of - or indeed danced to - Gangnam Style by the South Korean pop singer Psy.

The song became a global phenomenon, but it is far from the only cultural export from South Korea to win a vast international following.

And as Euny Hong, author of The Birth of Korean Cool: How One Nation Is Conquering the World Through Pop Culture, that success is no accident.

She talked to the BBC about the South Korean government's long-term project to influence foreign affairs through K-pop and dance moves with military precision.

Produced by the BBC's Regan Morris and Bill McKenna

Picture This is a series of video features published every Thursday on the BBC News website which illustrate interviews with authors about their new books.