Brad Pitt has praised his 12 Years a Slave co-stars for delivering amazing performances in such "demanding" roles.
The Hollywood actor produced the Steve McQueen film, which tells the real-life story of Solomon Northup, a slave living in freedom in New York in the 1850s who is enticed to go on a trip to Washington only to end up being kidnapped and sold into slavery.
Pitt played down the role he had in the film, saying that his co-stars Michael Fassbender, Chiwetel Ejiofor and Lupita Nyong'o deserve all of the attention.
He told US breakfast show Today: "I'm there (onscreen) to support the story. The main performances are Chiwetel Ejiofor, Lupita Nyong'o, Fassbender. These are such demanding parts. These guys had to keep themselves in a perpetual state of angst and foreboding and longing and they did it, they did it. They held themselves through the entire filming process."
Pitt added that the film will make an impact on audiences for years to come, saying: "I know what this film is. I've been around film long enough. I know the impact, and this one will have a continuing impact... It's one of those few films that cuts to the base of our humanity.
"And it was not until I saw Solomon Northup's story that I fully, fully grasped the utter horror of losing your freedom or denying another one their freedom, taking their freedom, splitting their family apart."
Fassbender is a frontrunner to receive a Best Supporting Actor nomination for next year's Oscars for his role as a sadistic plantation owner, but he has insisted that he won't go on the campaign trail this year.
He told GQ: "You know, I get it. Everybody's got to do their job. So you try and help and facilitate as best you can. But I won't put myself through that kind of situation again. It's just a grind. And I'm not a politician. I'm an actor."