After over a year of speculation, "Fifty Shades of Grey" has finally found its leads. "Sons of Anarchy" star Charlie Hunnam will play Christian Grey and Dakota Johnson, the daughter of Don Johnson and Melanie Griffith, will take on Anastasia Steele.

Author E L James made the announcement over a series of tweets on Monday (September 2). "Good moaning all. Hold on to your hats...," she teased before dropping the big news.

I am delighted to let you know that the lovely Dakota Johnson has agreed to be our Anastasia in the film adaptation of Fifty Shades of Grey.

— E L James (@E_L_James) September 2, 2013

Johnson's first big film role was in "The Social Network," and she's since appeared in "21 Jump Street" and "The Five Year Engagement."

That left the much sought-after role of Christian Grey, for whom actors like Ian Somerhalder and Alexander Skarsgard were reportedly once in the mix. "So ... Christian...," she tweeted, and then delivered the news.

The gorgeous and talented Charlie Hunnam will be Christian Grey in the film adaptation of Fifty Shades of Grey.

— E L James (@E_L_James) September 2, 2013

Hunnam's film credits also include "Pacific Rim" and "Cold Mountain."

The best-selling book trilogy follows the unlikely relationship of billionaire tycoon Christian Grey and vulnerable college student Anastasia Steele who undergoes a sexual awakening. The racy "Fifty Shades" became a global phenomenon, selling over 70 million copies worldwide and putting erotic romance back on the literary map.

With casting in place, the film's core team now consists of Sam Taylor-Johnson ("Nowhere Boy") as director, Kelly Marcel (Fox's short-lived "Terra Nova") as screenwriter and Michael De Luca and Dana Brunetti ("Social Network") as producers. The film is scheduled for a summer 2014 release.