The filmmakers of "Fifty Shades of Grey" have a lot of work to do when it comes to casting.

Many fans already know who they want to play certain parts in the book, and that includes Ethan Kavanagh.

Ethan is Kate Kavanagh's brother. [SPOILER] He gets involved with Mia Grey, Christian Grey's little sister. At first it doesn't seem like Ethan is into her, but they eventually get together. Anastasia Steele is also close to Ethan.

Ethan is described as "sun-bleached blond hair, a tan to die for and glowing hazel eyes."

One big fan favorite to play Ethan is "Supernatural" star Jensen Ackles.

FiftyShadesExaminer on Twitter tweeted to @DanneelHarris, saying "You need to convince your husband to push for the role of Ethan in #FiftyShades - He was made for that part!"

A Tumblr account features Ackles as Ethan, Elliot Grey or Christian Grey.

Many fans believe that the 34-year-old actor can play Christian Grey the best. A Pinterest page features many photos of Ackles as the sexy billionaire Christian.

The Examiner reported that Ackles has the looks to play either part in the "FiftyShades" film. The website said:

"Yet he seems to truly personify Christian Grey. Jensen Ackles may not be part of the erotic BDSM world but he has many other traits that make him perfect for the role.

"Jensen has a quiet confidence and the charisma to charm any woman. As seen in interviews, he also has the presence needed to play the very wealthy Grey Enterprise Holding's CEO.

"Christian Grey is a skilled, yet modest, pianist and singer. There are many scenes from the book where Ana Steele finds Christian playing the piano alone. She is in awe of his abilities and grows a deeper love for the complex man. Jensen Ackles is known for being a talented singer and guitar player, often taking the stage for jam sessions. While on the series "Dark Angel", Jensen also played a Chopin piece on the piano.

"He went on to say, "I grew-up with piano in my house." Yet another reason why Jensen Ackles personifies Christian Grey."

According to What Culture, Ackles is listed as number one on their list of ten actors that should play mysterious Christian Grey.

"Ackles would bring the necessary dark mystique, and he is another actor who has been suggested by fans," What Culture wrote. "He would certainly be a marketing savvy pick, because fans of Supernatural have been calling out for the opportunity to see him in a more erotic role for some time now."

The bad news is that he might be just a little too clean-cut for the part.

Ackles plays Dean Winchester on "Supernatural." Most of the time he's busy hunting down supernatural beings, such as vampires and fallen angels, with his little brother Sam (played by Jared Padalecki).

Some actors up for the role of Ethan are Zac Efron, Liam Hemsworth, Chace Crawford, and Alex Pettyfer.

Many actors are up for the role of Christian Grey and they include Matt Bomer, Ian Somerhalder, Robert Pattinson, Henry Cavill, Jessie Pavelka, and Colin Egglesfield.

The "Fifty Shades" trilogy ("Fifty Shades of Grey," "Fifty Shades Darker," "Fifty Shades Freed"), written by E.L. James, tells the story of 22-year-old recent college grad Anastasia Steele, who enters into a dominant/submissive sexual relationship with 27-year old sexy billionaireChristian Grey, and both explore Christian's world of BDSM while trying to understand their complicated relationship.

Which role does Jensen Ackles seem better to play: Ethan Kavanagh or Christian Grey? Sound off below!

Click HERE to see who the front-runners were last week for Christian and Ana.

Click HERE to vote for Christian Grey!

Click HERE to vote for Anastasia Steele!

Vote for your favorite couples to play Ana and Christian HERE!

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