A movie showing the effect former South African President Nelson Mandela had on a prison warden has had its premiere at the Berlin Film Festival.
The film stars Dennis Haysbert and British actor Joseph Fiennes
Based on the memoirs of James Gregory, who guarded Mr Mandela for 20 years, it features ex-24 star Dennis Haysbert as the jailed anti-apartheid campaigner.
Haysbert told reporters it had been "daunting" and "intimidating" to take on the role in Goodbye Bafana.
"Every night I went home, I would have a glass of wine and just cry," he said.
"The sacrifices he made were profoundly sad to me."
Goodbye Bafana is competing for the Golden Bear award, which is the Berlin festival's top prize.
It co-stars British actor Joseph Fiennes as Mr Mandela's prison guard, who builds up a relationship with the civil rights leader during his 18-year stay at the maximum security jail on Robben Island.
Fiennes said it had been a challenge to play James Gregory, who originally believed Mr Mandela should have been hanged as a terrorist.
The actor said the key to understanding his character was to realise he had been subject to "a certain conditioning which is pretty scary and abhorrent at times".
Joseph Fiennes plays prison guard James Gregory
Gregory, who died in 2003, worked in the office that handled prisoners' mail and was responsible for censoring Mandela's letters.
He passed on information to the security police which he later realised was used to target members of the struggle against apartheid, the system which promoted white minority rule in South Africa.
Over the course of the film, Gregory's prejudices are challenged by Mr Mandela's courage and respect for those who hate him.
The historical context is given through real news footage of riots and speeches from the period.
Mr Mandela has never confirmed Gregory's claim that they had become friends and it was reported that he considered suing the jail warden over his book.
Mandela spent 18 of his 27 years in prison in this cell on Robben Island
His official biographer, Anthony Sampson, says Gregory rarely had contact with Mr Mandela, but gleaned details from letters he censored to fabricate a friendship.
Director Bille August sought to play down questions over the accuracy his film, saying he had not included some of the more controversial claims from Gregory's book.
"This is something we have totally avoided in our story," he said.
"It's only natural in a country like South Africa there would be a lot of different points of view of reality."
Fiennes said he regretted not having met Gregory "because it is hard to know where the truth is".