Now, they know: On Monday, author E L James Tweeted, "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."
The daughter of actors Don Johnson and Melanie Griffith, Johnson, 23, is a model-turned-actress who has been seen in The Social Network and the short-lived sitcom Ben and Kate.
Over the past year she was just one of the many names mentioned as being up for the coveted role.
Among the other possibilities were rumored to be Emma Watson, Shailene Woodley and Analeigh Tipton.
Less than an hour later, James also put speculation to rest about the male protagonist.
"The gorgeous and talented Charlie Hunnam will be Christian Grey in the film adaptation of Fifty Shades of Grey," she Tweeted Monday.
Perhaps best known for his portrayal of Jackson "Jax" Teller on Sons of Anarchy, Hunnam, 33, also played Raleigh Becket in this summer's sci-fi adventure Pacific Rim.