Dornan rose to fame with his portrayal of Christian Grey in erotic-romance "Fifty Shades of Grey", adapted from EL James's book of the same name. Earlier he played a serial killer in "The Fall".
"I consider myself quite light-hearted, pretty easy-going, and I keep playing sick psychopaths. It kinda worries me sometimes how comfortable I am in that zone," Dornan told the Guardian.
The Irish actor said he sometimes finds it comical that he brought Grey's character to life on screen.
Dornan, 32, and actress Dakota Johnson will be a part of the two follow-ups to "Fifty Shades of Grey".