The 50-year-old star instead took a relatively smaller role of a decent Canadian worker in the Steve McQueen directed movie, which has been nominated in nine categories at the Oscars including the best picture and best director.
"I didn't want my kids to see me in this role," Pitt told Mirror.
The role of the plantation owner and cruel slave master Mr Epps was eventually played by Michael Fassbender, who has previously collaborated with McQueen on 'Shame.
'12 Years a slave' is one of the most buzzed films in the lead up to the Oscars. The film bagged the Golden Globe Award for Best Picture Drama.
It is slated to release in India on January 31.