CBS said De Niro and his "Little Fockers" co-star Dustin Hoffman taped an interview this week for the chat show to be broadcast Friday.
"We've been on the air for 30 years. Right now, we're on CBS. We used to be on NBC. I live in your neighborhood, literally, your neighborhood. We're neighbors, and this is your first time -- what have I done?" Letterman teased De Niro, star of "Raging Bull" and "Taxi Driver."
"Oh, God, I don't know," De Niro replied. "I just -- well, whatever. Dustin, he'll explain to you."
"All right, Dustin, what's the story?" Letterman asked with a laugh.
"If you ask me the questions that you have designated for Bob," Hoffman replied, "I can maybe answer for him."
"You know," Letterman said, "this is not a legal proceeding."
"I am 'the De Niro Whisperer,'" Hoffman quipped as De Niro smiled.