See Chiwetel Ejiofor reading from Solomon Northrup's "12 Years a Slave":

It's pretty much common knowledge that Steve McQueen's historical drama "12 Years a Slave" is based on the real-life experiences of Solomon Northop. Now, a behind-the-scenes clip from the Blu-ray release of the Oscar-nominated film discusses just how unique Northop's story really is.

Solomon Northup was a free man in New York who was kidnapped and sold into slavery in 1841, enduring a dozen years of emotional, mental and physical hell before being rescued in January 1853. Our exclusive clip opens with "12 Years" star (and Best Actor nominee) Chiwetel Ejiofor reading from Northop's book, "Twelve Years a Slave," in which Northop writes that "it has been suggested that an account of my life and fortunes would not be uninteresting to the public."

[Related: '12 Years a Slave’ and ‘Gravity’ Win Big at BAFTAs]

From there, Harvard University professor and historical consultant Henry Louis Gates Jr. reveals that of the 101 books written or dictated by people who once were slaves, Northop's is the only one that addresses the experience of a free man or woman in the North who was taken into slavery in the South.

And a remarkable account it is, as Northop's intelligence and photographic memory make for a startlingly detailed record of his experience, one that Gates Jr. claims has "a level of verisimilitude" missing from many other slave stories. "No white man living in upstate New York could've fabricated this narrative," he says.

[Related: '12 Years a Slave' Underscores Scourge of Modern Slavery]

"I really have no doubt that the story is true," adds Solomon Northup biographer David Fiske. "The vast majority of everything in his book checks out and holds up to historical study."

The clip will be featured on the Blu-ray of "12 Years a Slave," available on March 4. Two days earlier, the film will be honored at the 86th Annual Academy Awards ceremony, as it's nominated for nine Oscars: Best Picture, Actor, Supporting Actor, Supporting Actress, Director, Adapted Screenplay, Film Editing, Costume Design and Production Design.

See Behind-the-Scenes footage from "12 Years a Slave":