Michael Moore looked healthy, De Niro and Keitel looked chummy, Jodie Foster looked glamorous and Cybill Shepherd looked seriously happy as they arrived Thursday night at the Beacon Theatre on Manhattan’s Upper West Side for the Tribeca Film Festival screening of Taxi Driver. The occasion was the 40th anniversary of Martin Scorsese’s touchstone 1975 film of ratty Vietnam-era NYC and Travis Bickel, a fictional denizen of ratty Vietnam-era NYC who, like Ratso Rizzo and Popeye Doyle long ago entered the iconography of that time and place.

The screening provided the excuse for a reunion and gathered on stage to reminisce were Scorsese, De Niro, Foster, Shepherd, Keitel, screenwriter Paul Schrader and producer Michael Phillips, interviewed by Film Society of Lincoln Center head Kent Jones. Schrader said that Travis was a part of himself that he feared and therefore had to confront by writing about him. Scorsese was in post-production on Mean Streets and looking ahead to Alice Doesn’t Live Here Anymore but was taken with the screenplay as a quintessential story of the times. The production window was small and the budget was limited; the summer of shooting was hot and humid and continuous thunderstorms regularly thwarted the filming schedule.

But perhaps the trickiest part of assembling the film, Scorsese and Phillips recalled, was bringing the famed film composer Bernard Herrmann on board. “I don’t do movie about taxi drivers,” Herrmann told Scorsese when the director first approached him. But he read the script and “he liked it,” Scorsese said, “especially when Travis poured peach brandy on his cereal in the morning, He really liked that.”

Watching the film, one could easily find the score overbearing, announcing the growing tension and coming violence of the film’s ending — scores more reminiscent of his work for Rod Serling’s Twilight Zone than for Alfred Hitchcock’s thrillers. But Herrmann had a reason for scoring Taxi Driver so provocatively, Scorsese said: In his other work, he composed according to the kind of music each character might listen to. “But there was no music in Travis’ life,” Scorsese said. Instead, the score reflected the deterioration of Travis’ mental state — which was a revelation that made a great deal of sense.

Jones asked Keitel, who in the film plays the pimp Scout to Foster’s 13-year-old prostitute Iris, about rumors that he had engaged the services of a pimp to prepare for the role. “Is the statute of limitations over for that yet?” Keitel asked.

Prodded by Jones and a complicitous audience, Keitel recalled that he was performing on Broadway when they were putting the film together (playing son Happy to George C. Scott’s Willy Loman in a revival of Arthur Miller’s Death of a Salesman) and, after the show, sought advice from the working girls of Hell’s Kitchen. Seeing he was getting nowhere, one of them finally told him he was wasting his time because, marquee name or no marquee name, no one was going to talk to him. Keitel seemed ready to end the tale there, but after more urging from the enthusiastic crowd, he admitted that he had ultimately spent some time with “a former pimp” for pointers.