Charlie Hunnam has already said he is confident he will live up to fans expectations when it comes to the steamy sex scenes in the movie "Fifty Shades of Grey." The 33-year-old actor has no problem getting down and dirty for the camera.

Now screenwriter Kelly Marcel is promising the movie will be hot-and-heavy as well. According to Hollywood.com, Marcel is determined to keep the movie "as raunchy and sexy as possible."

"We are 100 percent going there," Marcel told The Sunday Times. "It will be rated NC-17. It will be raunchy."

Universal Pictures, the studio behind the film, has not officially gave "Fifty Shades of Grey" a rating yet. There has been concern in the past about an NC-17 rating because it could end up excluding people from seeing the film and as Hollywood.com points out, a lot of the bigger movie theaters don't play films with such a restrictive rating.

"She is going to have to walk a very fine line," Melissa Silverstein, editor of Women and Hollywood blog told indiewire.com. "That's the $1,000 question. Are they going to push things to a different level?"

According to USA Today, the higher ups involved in the movie want to keep it as an R-rated movie because NC-17 is often looked at a "kiss of death." There are ways around this however. The actual movie could very well, if creatively done, stick to the steaminess fans want to see in the movie but keep the really explicit and graphic scenes for a DVD release.

Regardless which direction they decide to take the movie will have only once shot to get it right. Charlie Hunnam and Dakota Johnson have reportedly both signed on to do two more movies but according to several reports the success of the first movie will determine if there are sequels.

Fans already boycotted the casting decision so executives and producers need to impress when it comes to the actual movie. The first chance fans will get to glimpse the movie is rumored to be around the Super Bowl when an official trailer is expected to be released.

"That first look will be everything," Erik Davis, contributing editor for Fandago told USA Today. "It will show the world just how much chemistry these actors have together. That trailer will prove whether there will be a 'Fifty Shades of Grey' franchise."

In the meantime an unofficial trailer starring Charlie Hunnam and Dakota Johnson has already made its round on the Internet. Check it out below.