Since the official announcement on Monday, fans of the much anticipated film  can't help but express their disappointment for the Fifty Shades of Grey cast.

In a series of tweets, E.L. James,  the author of the fastest-selling paperback, revealed that Charlie Hunnam and Dakota Johnson bagged the coveted roles of Christian Grey and Anastasia Steele.

Upset fans expressed that their expectations have not been met. These rants were apparently noticed by the film's producer, Dana Brunetti. In his own Twitter page, he publicly justified their choices: "There is a lot that goes into casting that isn't just looks. Talent, availability, their desire to do it, chemist with other actor etc."

He also asked fans to think before going on with their tirades: "If you're favourite actor wasn't cast, then it's most like due to something on that list. Keep that in mind while hating and keep perspective."

Michael De Luca, another producer of the film, also tweeted about the positive outcome of the auditions: "Auditions were stunning, incredible chemistry!"

Since late 2012, readers of the provocative trilogy have been declaring their celebrity bets for the roles. Matt Bomer, Henry Cavill, Ian Somerhalder, and Ryan Gosling were some of the names that have been linked with the business magnate-slash-sadist Christian role.

On the other hand, several A-list actresses were thought to assume the role of the naïve Ana. These include Emma Watson, Alexis Bledel, Mila Kunis, and Emilia Clarke.

Both Johnson and Hunnam reportedly tried out several scenes from the sadomasochistic novel to prove their chemistry. The up-and-coming Johnson contributed minor roles in 'The Social Network', '21 Jump Street,' 'Beastly', and 'The Five-Year Engagement'.

While E.L. James's first choice for the brooding Grey is Robert Pattinson, producers went for the British hunk Hunnam who recently appeared in 'Pacific Rim'.

The film, which will be directed by Sam Taylor-Johnson, is slated for release in August 2014.