Actor Chiwetel Ejiofor says he was "not prepared" to watch for the first time 12 Years a Slave, the film which marked a turning point in his career.

The 2013 biographical drama, directed by Steve McQueen, featured Ejiofor as Solomon Northup, a New York State-born free African-American man who was kidnapped in Washington, DC by two conmen in 1841 and sold into slavery. He was put to work on plantations in the state of Louisiana for 12 years before being released.