Robert De Niro was on hand to celebrate the 50th anniversary of Taxi Driver this week at a Tribeca Film Festival screening. On Friday (June 5), during a panel that included De Niro, Taxi Driver director Martin Scorsese , actor Jodie Foster , screenwriter Paul Schrader and comedian W. Kamau Bell , the latter asked the two-time Oscar-winning actor to recite the movie's memorable line because the crowd would "go nuts." To the delight of attendees, De Niro fulfilled the request and threw in another line as a bonus. "Are you talking to me?" said De Niro, who played protagonist Travis Bickle in the 1976 blockbuster. "I'll add one more thing. I'm the only one here. That's the point." Taxi Driver , which co-stars Foster, Cybill Shepherd, Harvey Keitel and Albert Brooks, was nominated for four Academy Awards, including Best Picture and Best Actor, but lost in both categories to Rocky and late actor Peter Finch, star of Network .…