"Fifty Shades of Grey" is not only a best selling trilogy, it's also fast-becoming the most anticipated movie for 2015. So why did "Sons of Anarchy" star, Charlie Hunnam, pass the opportunity to play Christian Grey to Jamie Dornan? 

The hunk, who had originally accepted the role of the business magnate and S&M-loving character, revealed why he turned down one of Hollywood's biggest roles.

The 34-year-old heartthrob admitted that it wasn't only a project conflict -- he also suffered anxiety issues. Speaking to Us Weekly during the Television Critics' Association party last month, he expressed that he really wanted to do the film.

"I wouldn't have signed up in the first place if I didn't want to do it," he explained. "It was a really, really difficult time in my life. I had already been attached to Crimson Peak for about 14 months, which I said, I was going to do with Guillermo [del Toro]."

Hunnam detailed the excitement and anticipation that built in him as an artist after he and director Sam Taylor-Johnson hit it off in a meeting.

"Sam and I just fell in love, creatively," Hunnam recalled. "We started talking about this thing and I just felt so excited. I fell in love with the character and started seeing him and becoming intoxicated, which is the way I work: I find a character I love and I start thinking about it all the time," he revealed to the publication.

During that time, he had three commitments, making his schedule very tight. To elaborate, Charlie outlined, "I was going to finish [filming] 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."

After two months of being officially cast as the lead role, Hunnam announced he was dropping out of the film. Admitting he bit off more than he could chew, it was a decision he found difficult and one he didn't want to make.

"I just said, 'I can't...I can't. To fail on such a grand scale-because Fifty's going to be massive, it's going to be huge. I really didn't want to fail on such a grand scale and I just couldn't transition from Jax to Christian Grey in 48 hours," described the rugged, bad boy of the ordeal.

He refers to it as a "S**t situation" because of his connection and love for the character.

Thankfully, Hunnam is "doing good" and concentrating on work. "It's been a really busy time," he said to E! News.

See the trailer of "Fifty Shades of Grey" starring Jamie Dornan and Dakota Johnson. The film hits theaters February 2015.