The actress told Collider that Merlin (Joseph Fiennes) won't have "the pointy hat and the white beard".
"He's a very charismatic, powerful actor," she said. "He has a very strong presence. Even if he doesn't talk, he's extremely powerful [and] I love the fact that he's a very different Merlin."
She continued: "He's... quite damaged [and] he's a sexy Merlin."
Green added that her co-star Jamie Campbell Bower will portray a "rock 'n' roll" interpretation of Prince Arthur.
"[Jamie is] much fun," she explained. "He's very naughty. He's wonderful. He doesn't take himself seriously and he's very humble."
The Casino Royale star also claimed that her own character Morgan is "damaged" rather than "evil".
"She believes herself to be the rightful heir to the throne," revealed Green. "But because she’s a woman, she’s denied the throne and she will do absolutely anything to get it back."
Camelot premieres on April 1 on Starz.