Although Jamie Dornan was cast as Christian Grey in the film that opens Valentine's Day 2015, former Fifty Shades of Grey star Charlie Hunnam is still talking about the movie he was originally in.

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"I wouldn't have signed up in the first place if I didn't want to do it," Hunnam told Moviefone on Monday about Fifty Shades. "It was a really, really difficult time in my life."

Hunnam blamed scheduling between his TV show Sons of Anarchy and Fifty Shades of Grey for him having to drop out of the project. "I was going to finish Sons at like 11 p.m. Friday night, get on the plane Saturday morning to Vancouver for Fifty, missing the whole first week of rehearsal and start shooting Monday morning. And I was going to shoot that film, wrap that on the Wednesday and the following Monday I was going to start shooting Crimson Peak in Toronto. I just had like ... frankly, something of a nervous breakdown."

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Fans protested originally Hunnam's casting in the sexy film adaptation and Hunnam admitted he was nervous about the role. "I really didn't want to fail on such a grand scale and I just couldn't transition from Jax Teller to Christian Grey in 48 hours. I bit off more than I could chew and it was painful," he said. "I loved the character and I wanted to do it."

Sons of Anarchy is in its final season, while Fifty Shades comes out February 2015.