And, call it reason No. 51, but if the producers had somehow got the casting of Christian Grey and his sexual protégée, Anastasia Steele, wrong...talk about your flaccid endeavors.
Dakota Johnson's willingness to do full-frontal nudity aside, not every pair of hot actors are automatically fit to be tied (to the hottest project of the year, that is).
In fact, it turns out that Universal Pictures didn't want to take any chances that Hunnam wouldn't mesh with the onscreen object of his affection in the adaptation of E.L. James' best seller, so the pair were required to do a "chemistry read" before any contracts were signed, according to The Wrap.
But they weren't just reading, of course.
One day it will probably be offered up to the Internet gods, but for now, just be secure in the knowledge that there's a screen test featuring Hunnam and Johnson testing out their sexual chemistry out there, somewhere.
Moreover, per The Wrap, Hunnam didn't want to sign on until he had a, er, firm grip on who his costar would be, and he read with several actresses before Johnson became the clear front-runner.
Apparently that chemistry read convinced everyone who needed to be convinced.
Fifty Shades of Grey is due in theaters Aug. 1, 2014, with sequels Fifty Shades Darker and Fifty Shades Freed presumably to follow in subsequent years.