Surprisingly, the British actor says he's still struggling with the aftermath of dropping out of the film adaptation of E.L. James' Fifty Shades of Grey. Hunnam was initially cast as Christian Grey (the role eventually went to Jamie Dornan) in September 2013, but dropped out a month later, citing scheduling conflicts.
"Oh it was the worst professional experience of my life," he admits to the magazine. "It was the most emotionally destructive and difficult thing that I've ever had to deal with professionally. It was heartbreaking."
Hunnam explains that he was forced to drop out after already committing himself to Guillermo del Toro's Crimson Peak, and having to finish up Sons of Anarchy. The decision was obviously devastating for Fifty Shades of Grey director Sam Taylor-Johnson.
"I called her and we both cried our eyes out on the phone for 20 minutes," he shares. "I needed to tell her that this was not going to work. ... There was a lot of personal stuff going on in my life that left me on real emotional shaky ground and mentally weak. I just got myself so fu**ing overwhelmed and I was sort of having panic attacks about the whole thing. I just didn't know what to do."
Still, despite reports, he insists that his decision had nothing to do with being hesitant about filming explicit sex scenes from the erotic novel.
"When I was 18 I was getting fu**ed in the ass, completely naked on national TV, y'know?" he points out, referring to his role on Showtime's Queer as Folk.
Despite his blunt nature, Hunnam does show his sentimental side in the new chat, particularly when it comes to saying goodbye to his character, Jax, on Sons of Anarchy.
"I smoked a few joints and sat on the back lots and cried a bunch and said goodbye to him," he says about coming back on set after filming wrapped. "It was beautiful and it was the right thing to do. I took my rings, my bike, my jacket, my knife -- f**king a lot. Anything that wasn't nailed down, I took."
ET caught up with the handsome star last November, when he revealed the secret to his amazing physique. "I’ve been going to the gym and doing 75 dips, 75 pull-ups, 150 push-ups, 150 squats, and 20 minutes of abs," he shared. "After my abs, I do the back extensions."