The Oscar-nominated star, who plays veteran spy George Smiley in the film, admits he has always been puzzled by Ian Fleming's flamboyant hero.
Oldman explains, "He's (Smiley) the polar opposite of Bond. He is the man in the mac who you would pass in the street and not look at twice, whereas Bond, it's always struck me, announces who he is everywhere he goes - to the villain, to the guy that wants to kill him.
"He wears a white tuxedo and you go, 'Where's Bond...?' He's just pulled up in the Aston Martin... I've always found that strange.
"(It's like), 'I'm Bond, kill me!'"