Fifty Shades of Grey movie has finally made a major leap in casting. Erotic series author E.L. James has just announced on Twitter that Dakota Johnson is playing Anastasia Steele. Christian Grey announcement is expected soon. A lot of fans have expressed disappointment, but James' announcement sounds final.

Anastasia Steele in James' Fifty Shades of Grey starts off as a "sex innocent" who gets drawn to Christian Grey's magnetism and sex appeal. Her best friend Kate Kavanagh warns her Mr Grey can be dark and dangerous, but she falls for him anyway. Dakota Johnson's FSOG BFF Kate has yet to be named, as well.

Anastasia and Christian engage in steamy sex and bondage acts in Grey's playroom, wherein she discovers the intricacies of being a sex submissive. Nudity, adult language and elaborate sex scenes are expected in the raunchy movie. It is understood Dakota Johnson has read the script, as written for the big screen by Kelly Marcel.

"Good moaning all. Hold on to your hats," E.L. James tweeted just minutes before announcing that Dakota Johnson "has agreed to be our Anastasia."

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

Replying to E.L. James' Twitter announcement are several 'Fifty Shades of Grey' fans who expressed mixed reactions.

@E_L_James WE DONT CARE, WHO'S GOING TO PLAY CHRISTIAN?!?? — Messer✌ (@JessicaAnnH) September 2, 2013

As if hinting disappointment over Dakota playing Anastasia, this Twitter user is short of begging for a good Christian Grey:

@E_L_James @EverythingFifty please let Christian be someone that is hot — Michelle Holmes (@pawspastries) September 2, 2013

Here's another disappointed Fifty Shades of Grey fan, who said Dakota Johnson's photos do not show "Anastasia Steele material:"

@E_L_James Just looked up a picture of Dakota & she's not Anastasia Steele material #disappointed — Erika Gudino (@crazyerika72) September 2, 2013

On Tumblr, fans are also airing disappointment over the casting for Anastasia Steele. One user even posted Dakota's photo side-by-side with Alexis Bledel, one of the top fan favourites for the role.

Among actresses whom fans shouted out for the FSOG Anastasia role are Nina Dobrev, Lauren Watson, Lucy Hale.

More Entertainment Features:

'Fifty Shades of Grey' Movie Casting: Producers' Top Three Choices for Christian Grey [PHOTOS]
Cote de Pablo's Ziva David Replacement Named as Bishop, NCIS Season 11 Spoilers [VIDEO, PHOTOS]
Mermaids in True Stories or Mere Mockumentaries? Maybe You Can Hire One for Under $2,000! [VIDEO]

Twitter