The Hollywood heavyweight stars alongside Al Pacino and Joe Pesci in Martin Scorsese's new crime drama about connections between the mafia, labour unions and US politics in in the 1960s.
The plot spans several decades, and special software was used in post-production to make De Niro and his co-stars look younger at certain points.
"It's great that we had this de-aging thing that would work," he said.
"Originally, we were talking about how we would possibly have younger actors play us. And then as time went on with this thing going so long the technological part of it started getting stronger," he added.
"The Irishman," based on true events, began a limited theatrical release on November 1, and will be available for live-streaming on Netflix on November 27.
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