(CNN) -- Charlie Hunnam didn't drop out of "Fifty Shades of Grey" because he didn't want to play the lead, Christian Grey.
He dropped out because the timing had him on the verge of a nervous breakdown.
"I wouldn't have signed up in the first place if I didn't want to do it," the "Sons of Anarchy" actor, 34, has said. "It was a really, really difficult time in my life."
That part, the actor now says, is true. Between his work on FX's "Sons" and his commitment to Guillermo del Toro's 2015 release, "Crimson Peak," there just wasn't a lot of room for "Fifty Shades of Grey" no matter how badly Hunnam wanted it to work.
"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," Hunnam said. "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."
The intense reaction to the "Fifty Shades" casting news didn't help. Fans were particularly livid about Johnson landing the part of naive student Anastasia Steele, but Hunnam also felt the pressure.
"I just said 'I can't' ... to fail on such a grand scale," Hunnam recalled. " '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 ('Sons of Anarchy's') Jax Teller to Christian Grey in 48 hours. I bit off more than I could chew, and it was painful. I loved the character, and I wanted to do it."
Instead of Hunnam, moviegoers will see relative newcomer Jamie Dornan in the role of Mr. Grey.
The film, which recently debuted its first trailer, opens February 13.