For his Oscar-winning role as the young Vito Corleone in "The Godfather Part II," De Niro took Marlon Brando's character one step further: He learned a Sicilian dialect. In the entire film, De Niro barely speaks a word of English.
"It's very difficult. I only learned the pieces that I had to for the scenes," De Niro said, "because to learn those pieces and try and speak it with the proper accent, inflections and blah blah blah, you have to practice it a lot. It's just practice."
It all started in 1943, when he was born to parents Virginia Admiral and Robert De Niro Sr., in Greenwich Village, New York.
Both were accomplished painters -- his father, a figurative artist whose works have been celebrated in galleries all over the country.
"My father was an artist since he was, I think, five," said De Niro.
Dozens of his father's paintings adorn the walls of De Niro's restaurants in New York: "He was very particular that they were hung right and put up right, you know?"
He's even kept his father's art studio the same as the day he died. "Because I wanted the kids to know who their grandfather was," he explained. "I just felt it was important."
He wants the world to know more about his father, too. He's currently working on a documentary, set to air later this year, that will help De Niro Sr. "get his due," his son said: "He was the real thing. All of his work I can't not but make sure that it's held up and remembered."
Unlike his father, De Niro Jr. never picked up a paintbrush; instead, he focused on a canvas of a different sort, the silver screen.
When asked if he imitated other actors when he was young, De Niro said, "I'm not sure if I did that. I don't know, but my mother thought I was funny."
"The first thing you did was, what?"
"'The Wizard of Oz,' the Cowardly Lion, which was when I was 10."
Think about that for a moment: The man who brought us Al Capone in "The Untouchables" and wise guy James Conway in "GoodFellas" started out as . . . the Cowardly Lion.
Maybe shy lion, though, is more apt. "I had read that getting up in front of people and performing was a tough thing at first," De Niro said. "Well, it's hard for, I think, a lot of actors to do but it's not like, it's not that easy for me, but you, you do it."
"Where you shy?"
"Yeah, part of me is shy, I guess," he replied. "You know the old story that actors are shy, then they get behind the character they play, you know? There's truth to that."
"Is that true for you?"
"In some ways, yeah."
He didn't only hide behind the heavy roles. De Niro eventually took his mom's advice, and tried being funny.