While some filmmakers are happy to rely on the same old formula, others are forever seeking a new approach to a tired genre. And with its nagging predictability, there isn't a trickier genre to refresh than the romantic comedy, because everyone knows that there's only one way these movies can possibly end.

Lily Collins and Sam Claflin in 'Love, Rosie'
Are Lily Collins and Sam Claflin stuck in the friend zone in 'Love, Rosie'?

With the British rom-com 'Love, Rosie', director Christian Ditter and Juliette Towhidi, adapting Cecilia Ahern's novel, have a distinctly unusual premise even if the conclusion is rather foregone. This is the story of two lifelong friends who are clearly attracted to each other but neglect to reveal their feelings, sending their lives in very different directions.

More: Read our review of 'Love, Rosie'

What sets this one apart is the extra-long time scale, as the events are spread out across about a decade. As Rosie and Alex, rising star Brits Lily Collins and Sam Claflin kick off the film by revealing their characters' feelings in a drunken kiss. Then they are separated by twists of fate (an unexpected pregnancy), geography (one moves to America) and a series of relationships, marriages and liaisons that keep them apart even as they work to maintain their friendship.

More: Watch the trailer for 'Love, Rosie'

Much of the enjoyment with a rom-com is watching each turn in the tale, driving the characters together, then apart, then ultimately together. Even if the ending is predictable, a solid cast can make each gyration of the plot entertaining. 'Love, Rosie' has a bit of a different approach to this: the characters are never "together" - they seem to keep missing each other, realising their passions at all the wrong times.

More: Check out Mimi & The Mad Noise Factory's soundtrack song for 'Love, Rosie'

Whether audiences will warm to this approach is still to be seen. The film opens in the UK this weekend, and will perhaps be seen more as a test of Claflin's box office power in the midst of his prominent 'Hunger Games' role. But you can bet the studios will keep an eye on it to also see whether audiences are willing to accept something just a bit different from the usual mould.