Revered method actor Daniel Day-Lewis was so taken over by the role of Abraham Lincoln in Steven Spielberg's new historical epic Lincoln that even the director referred to him as Mr. President on set.

Co-star Joseph Gordon-Levitt, who portrays Lincoln's son Robert in the much-anticipated film, admits he never met the real Day-Lewis on the set - because he was always deep in character.

The Dark Knight Rises star says, "He's not silly about it... but he does stay talking in that voice; he spent a year coming up with how he wanted the voice to sound and I never heard his (real) voice and I never called him Daniel until I was lucky enough to be there on the last day of shooting. I got to watch him shed the character.

"Steven Spielberg would be like, 'Mr. President, can you take a step to the left?' I would just say, 'Sir,' because he was my dad.

"But he would chat or make jokes in between takes... but you wouldn't wanna go up to him and be like, 'Oh, did you see The Avengers...?' He definitely was really focused."