Charlie Hunnam has spoken out about the sex scenes in the Fifty Shades of Grey big screen adaptation, insisting that they won't be "too much of a problem".

The Pacific Rim star has been cast as Christian Grey opposite Dakota Johnson as Anastasia Steele in the movie, casting choices which have been controversially received by diehard fans of the E L James novels.

Speaking about the sex scenes in the film, Hunnam told The AP: "You know what, I had such a baptism of fire with regards to sexuality on camera at the beginning of my career.

"I starred in the British Channel 4 miniseries Queer as Folk, where I played a young, gay character, and there were some incredible, explicit sex scenes on that show.

"Now I am 16 years older and more mature so I don't anticipate them being too much of a problem. It's like anything else, just an exciting challenge."

Hunnam also spoke about the impact on-camera sex scenes will have on his long-term partner Morgana McNelis.

He said: "Of course, it's difficult being with an actor, you know?" 

"She is required to share certain parts of me with the world that she wouldn't necessarily choose to do, but we have a great relationship, and she loves me and wants to be with me and we've been together a long time now, and I think she understands and has come to terms with the fact that there are certain elements of me that she is going to have to share.

"This is an extreme example of that, but thankfully we do have seven and a half years of history together, so it won't be a big problem."