Adapting a much-beloved novel to the big screen is tricky business, but it always helps if the book's fanbase is made up of teen girls. They're the most loyal fans on earth, able to turn the mopiest material into a global hit (see also the Twilight saga). The Fault in Our Stars started as a 2012 novel by John Green, and its tale of 16-year-old cancer patient Hazel touched a nerve with readers and critics alike for its earthy authenticity.

The Fault in Our StarsShailene Woodley and Alsel Elgort in 'The Fault in Our Stars'

An international bestseller, it didn't take long to plan a film version led by Oscar-nominee Shailene Woodley and Alsel Elgort, who also appear together in Divergent, based on another young-adult bestseller. Unlike the one-off The Fault in Our Stars, Divergent is the first in a series of books, so is being turned into a movie franchise, with the sequel Insurgent now in production. 

More: read our full review of The Fault in Our Stars

een fans also made hit franchises out of Twilight and The Hunger Games, although The Mortal Instruments and Beautiful Creatures movies have struggled to catch on. But the power of these fans can be seen in the way they power the box office. Even with a mixed critical response, The Fault in Our Stars opened in America to record-breaking business and ecstatic praise from the book's devotees, who turned out in droves for premieres as well as premium-priced fan events such as The Night Before Our Stars, at which the screening was accompanied by a simulcast Q&A with the cast.

So it's hardly surprising that Hollywood will continue to court this audience. 

More: watch the 'Fault in our Stars' trailer