TORONTO -- The first time a bewigged Benedict Cumberbatch entered the room and heard murmurs of "Wow," he knew he was on the right track.
"That's a great thrill, when you think, OK, something's working," he told reporters at a five-star hotel during the Toronto International Film Festival.
The London-born Cumberbatch went to great lengths to portray WikiLeaks founder Julian Assange in "The Fifth Estate." He donned contact lenses to darken the blue of his eyes, wore prosthetic teeth and trained with a dialect coach to capture both Mr. Assange's Australian accent and slight lisp with its distinctive "S" sounds.
"I've got softer features. I'm a little more angular, which sometimes makes me look a little weird and creepy with some of the [white blond] wigs, and that's not the intention at all. That's just the way I look. ... I've got a longer face, he's got a rounder face."
But beyond all of that, he wanted to play Mr. Assange in a balanced way and make him three-dimensional, a man at the forefront of a media revolution and a pioneer linked -- for good or ill -- with Daniel Domscheit-Berg, who took the alias Daniel Schmitt when working with the website dedicated to protecting whistle-blowers.
Played on screen by Daniel Bruhl (Niki Lauda in "Rush"), Mr. Domscheit-Berg would later write "Inside WikiLeaks: My Time With Julian Assange at the World's Most Dangerous Website," one of the books on which the movie is based.
The author calls Mr. Assange imaginative, energetic and brilliant as well as paranoid, power hungry and a megalomaniac. Mr. Assange has denounced that account as deceitful and called another movie source book, this one by Guardian journalists, toxic and biased.
"Daniel's no stooge, he's not this follower. He's a smart guy, he's an activist, he's incredibly pragmatic, he's not just this sort of blind acolyte," Mr. Cumberbatch said.
"I think Julian has a magnetic hold over people, and I think he's an incredible spokesperson for an extraordinary idea that was born out of his realization of it, and he has very complex relationships with people because of that."
Director Bill Condon sees Mr. Assange as having "a certain guru element" to him, and a visit to the home of Daniel's parents reinforces the difference between the two men.
"He is somebody who has really extracted himself from all the comforts of life -- certainly of middle-class life -- having a home, having a bed, having a steady girlfriend," Mr. Condon said of Mr. Assange. "Each time there are those moments of lashing out, it has to do with a sense of betrayal on Julian's part.
"That somehow this person who he thinks is thinking about the world in the same way actually isn't," the director added. "He gets to the parents' house -- a background of domestic comfort -- which means, yet again, this acolyte will never be able to really join him. He's lonely and alone yet again."
Mr. Cumberbatch tried to steer clear of character assassination, "which is so easy to come by because people want a headline, they want to grab something and run with a two-dimensional story.
"I like the way the film tackles that, I like the way that Julian talks about his appraisal in The New York Times for getting equal billing for the state of his socks, as for collateral murder," he said.
The leading man rightly calls "The Fifth Estate" a dramatization of events, adding, "This is a perspective, not the perspective. The film's central message is there's no such thing as objective truth, there's always going to be a personal truth. ... Journalism is about something that's powered by individuals, it's not about a consensus."
Nevertheless, Mr. Assange tried to dissuade the Brit from tackling the role in early email exchanges, and just days ago, the WikiLeaks founder told the Hollywood Foreign Press Association (whose members are best known for handing out the Golden Globes) that "The Fifth Estate" was "opportunistic and hostile."
Mr. Assange conducted the interview by Skype from the Ecuadoran embassy in London where he has been living since June 2012. He took refuge there to avoid extradition to Sweden to face questioning about alleged sexual misconduct.
Given all of this, it may be impossible to keep the message separate from the messenger.
"We obsess about that, I think, in culture, all the time. We can't just take an actor's work, we need to know everything about their personality," said Mr. Cumberbatch, who coincidentally has been the focus of red-hot attention from the media and public.
Dressed this day in a dapper blue suit, white shirt and gray tie, he is having enough moments for an entire theater company. That is thanks to his TV portrayal of Sherlock Holmes, the villain in "Star Trek Into Darkness" and upcoming work as a preacher and Southern slave owner in "12 Years a Slave," the tenderhearted man Little Charles in "August: Osage County" and the voice of a dragon in "The Hobbit: The Desolation of Smaug."
It was Mr. Cumberbatch's "extreme intelligence, great charisma and great voice" that persuaded Mr. Condon he was the right man for the role.
"There's also something about Benedict, there's something about the British stage actor where he's a natural entertainer. I think that was crucial to that part. Even as he's being so odd, he's always kind of weirdly enjoying himself."
Mr. Bruhl had the tougher role of the everyman who doesn't get the pyrotechnics but must hold his own against the one who does. "I'd met a number of people and it was sort of that love-at-first-sight breakfast with Daniel Bruhl," Mr. Condon said.
"It's this incredible openness, kindness, intelligence, wit and also generosity because I do think it's tough sometimes to play those parts and to see somebody else get the last word. I can't tell you how crucial Daniel Bruhl is to making the movie work."
It's Mr. Domscheit-Berg and his relationship with WikiLeaks that gives shape to the movie with a beginning, middle and end.
As for developments that came after production ended, the director said, "That's incredibly juicy stuff, but I don't know that [whistle-blower] Bradley Manning's desire to have a sex change operation really speaks to what's going on or the issues that are happening in this movie."
It opens in theaters today.