Fiennes told reporters in a recent teleconference he brushed up on his Arthurian legend and spent time speaking to "Camelot" writer-producer Chris Chibnall to prepare for his role of sorcerer in this magic-tinged, medieval world.
The "Shakespeare in Love" and "FlashForward" star said Chibnall made him feel as though their 10-episode fantasy-drama series wasn't going to be "an off-the-peg kind of 'Camelot,' which has been done."
"I got fired up by [the idea of] tackling Merlin in a fresher angle. I guess youth is a predominant factor; that we were seeing a young King Arthur and, thereby, a youngish -- really, I'm into my 40s -- Merlin," Fiennes said, adding his version of Arthur's magical adviser has a "Machiavellian, bipolar" way about him.
"He's not to be trusted, yet he is fighting for this great seat of power and is really sort of the master to some degree in orchestrating [the kingdom of] Camelot and King Arthur," the actor said. "So he's a strange, dark, devious character and I just wanted to have fun."
Fiennes -- whose older brother, Ralph, plays wizard-gone-bad Voldemort in the "Harry Potter" blockbusters -- said he also wanted to get away from the cloak, staff, long beard and pointy hat that have been the hallmarks of previous Merlin incarnations.
"Through Chris came the idea that [Merlin] was more a warrior monk that is coming to terms with his sort of -- his powers and how they can affect him and others," Fiennes said.
Co-starring Jamie Campbell Bower as King Arthur, Tamsin Egerton as Guinevere, Claire Forlani as Igraine, Peter Mooney as Kay, Philip Winchester as Leontes and Eva Green as Morgan, "Camelot" airs Friday nights on Starz.