The Sherlock star revealed that his character is neither good nor evil in the traditional sense, but kept his on-screen identity under wraps.
"He is very ruthless… He is not a clearly good or evil character. He is a villain but the actions he takes has intent and reason," Trek Movie quotes Cumberbatch as saying.
"He is a complicated character not to be judged by white-or-black, or good-or-evil. But this is the appeal of JJ's works and I felt challenged as an actor."
Cumberbatch also admitted that he was pleased to join the project, but felt trepidation knowing that it will be bigger in scope than its predecessor.
"I was a fan of the [2009 Star Trek], so I was pleased when I got the offer. But I know the second one will become far-bigger scale, so I felt terror instant," he said.
Star Trek, which sees Chris Pine and Zachary Quinto reprise their roles as Captain James Kirk and Spock, is released on May 17 next year.
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Photo gallery - Star Trek movies through the years: