The 40-year-old undertook extensive investigations cross-examine true accounts by meeting the CIA agent, reported Sun online.
"I really liked the idea that it was a true story. I did a ton of reading and a ton of interviewing. I went to the CIA, I read all the books," Affleck said.
To maintain accuracy and precision, Affleck said, "I spent time with (CIA agent) Tony Mendez and for the first-person accounts of this, then I did a lot of researching with hostages."
"Argo" is nominated in the Best Picture category at the Oscars to be held on February 24.