One Day Poster

While at the theatre yesterday seeing Trust, this poster for One Day literally stopped me in my tracks.  It's not terribly original or even very informative, but the sheer romance of it captured my interest in a way posters rarely, if ever, manage to.  Now the question is: do I read the book before seeing the movie, or allow the cinematic version to take precedence?  I'm leaning toward the latter option, if only because I'd never know the book exists were it not for the poster (and therefore, the movie).  Plus, going into romantic adaptations blind is the way to go.  Atonement blew my mind back in the day.