DeNiro's most famous line actually came from The Boss

Here's an interesting story -- at least I found it interesting. While preparing for his role in Taxi Driver, Robert De Niro attended a Bruce Springsteen concert during which the adoring crowd kept yelling Bruce's name. At one point, as the crowd is yelling "Bruce! Bruce!", Springsteen turned and said "You talkin' to me?"

A year or so later, De Niro is preparing for his role as a saxophone player in New York, New York and seeks out Springsteen's saxophonist Clarence Clemmons to show him the ins and outs of the instrument. While being tutored, De Niro tells The Big Man about his concert experience and confesses he stole what is unquestionably his signature line in Taxi Driver from The Boss that night.