Did Robert De Niro really ad-lib the "You talkin' to me" scene in Taxi Driver?

Question

Was it in the script or did he ad-lib.I've heard somewhere that he did.Is it true?

Answer 1

Yes, he did. I saw Martin Scorsese discuss that scene in a documentary retrospective about his directing career which I believe aired on Turner Classic Movie channel.

Answer 2

Neither. Scorsese had De Niro improvise that scene, but neither has ever (to my knowledge) said how many takes it took to get that scene as it appeared in the movie. Chances are more than one take was done, and other scenes may have been improvised as well but weren't use. Either way, the bit about "You talkin' to me?," wasn't in the shooting script. I suspect the entire scene came together only after a few attempts, during which the exact wording developed.