When five strangers flunked their X Factor audition in 2010, not even music mogul Simon Cowell could have predicted that just two years later they would have a Number One album around the world.
Niall Horan, Zayn Malik, Liam Payne, Harry Styles, and Louis Tomlinson had all passed initial auditions for the hit TV talent show but, having failed to impress at the following round, were set for an early exit.
Yet when show judges called them back to form a boy band, they had unwittingly created the beginnings of a pop sensation that would take the world by storm.
In fact, One Direction's success was so unprecedented that, within two years, they made history when they become the first UK act to enter the US charts at number one. By the end of 2012, the teenagers were boasting a string of awards and a collective bank balance of £100million.
All this, and the group had not even won the ITV show.
This is the incredible unofficial story of how, so far, One Direction have taken the world by storm.