Justin Chadwick and Idris Elba talk about bringing Mandela: Long Walk To Freedom to the big screen.

It was three years ago at the Toronto International Film Festival when producer Anant Singh first approached Justin Chadwick to direct a film about South African president Nelson Mandela.

But speaking during a press conference today following the world premiere of Mandela: Long Walk to Freedom, the British filmmaker admitted he was initially hesitant to sign onto the project, due to the responsibility that came with dramatizing the famous political figure.

“I knew how important it was to South Africa and I knew how important it was to the rest of the world,” he said. “How do you even begin to tell that story?”

For Singh, the answer was simple: tell the truth.

Adapted by British screenwriter William Nicholson from Mandela’s 1994 autobiography of the same name, Mandela: Long Walk to Freedom fills in the gaps left by previous Hollywood narratives, focusing on Mandela’s years prior to becoming a freedom fighter, including the tumultuous divorce and reported abuse suffered by his first wife Evelyn (who is played in the film by Terry Pheto).

That proved to be a challenge for leading man Idris Elba, who was forced to portray some of the darkest periods of the peaceful political figure’s life.

“I didn’t want to deface Mr. Mandela in any way,” Elba said during the press conference, “but I didn’t want to portray him in a way that wasn’t honest.”

“This is a guy with a profound sadness in him,” Nicholson added. “What we wanted very much to say was at the moment of his greatest victory, there was this sadness, the sense he lost what was central to his personal life.”

Unable to connect with the ex-president due to his ongoing health problems, Elba began researching for the role by travelling around rural communities, speaking with generations of South Africans about the impact Mandela played in their lives. He quickly discovered their acceptance with him portraying both the “saintly” and negative sides of his early career as a political figure, but made sure he understood it had to be done right.

“I wasn’t expecting to be accepted immediately as Madiba for various reasons,” Elba said, “but there was certainly the sort of willingness for us to go for it, but to know that you only have one chance.”

But as far as Elba is concerned, the movie wouldn’t have been done properly if they hadn’t covered the beginnings of the South African leader.

“He lived a very full life prior to that,” Elba said. “When you understand that, then you understand how long of a walk that freedom is.”