The Gangs of New York star was born and raised in London, but also has Irish citizenship because of his father's connections to the country.
He admitted his British background made him feel like a fraud for taking on the role of beloved U.S. President Abraham Lincoln.
He told the Daily Mirror newspaper: "I was very aware of the responsibility involved as I didn't want to be the person who desecrated the memory of the most loved president America has ever known... It seemed like an outlandish idea to take someone who grew up in south east London and make him President of the United States... I'm not an American citizen so I don't have the right to be president."
Day-Lewis previously admitted he had doubts about taking on the film project, but the gamble paid off.
He has received a Best Actor Oscar nomination for the role, as well as a nod at the upcoming British Academy of Film and Television Arts (BAFTA) Film Awards. He also won a Best Actor trophy at the recent Golden Globes.