The American actor, 80, confirmed in May last year that he and martial arts instructor Tiffany Chen had welcomed a child.
In an interview with AARP The Magazine, published by what was formerly called the American Association of Retired Persons, De Niro appears tearful as he speaks about his latest child, a daughter named Gia.
The Oscar winner, who was recently nominated by the Academy Awards for best supporting actor in western Killers Of The Flower Moon, said: "I'm an 80-year-old dad and it's great.
"Everything that I'm consumed with or worried about or this and that just goes away when I look at her so that in itself is wondrous.
"She has a very sweet kind of way of looking at you and just taking you in and my other daughter Helen had that too.
"(They) just look at you and take it in so I don't know where it's going with her later when she gets older.
"But she's thinking and she's observing everything and watching. It's really interesting. I (want to) be around for as long as I can to enjoy it, enjoy her."
De Niro, known for Taxi Driver and Goodfellas, has six other children from previous relationships with three women.
He has a son, Raphael De Niro, who starred alongside his father in Raging Bull, with actress and singer Diahnne Abbott.
He adopted Abbott's daughter from a previous relationship and shares twin sons with actress Toukie Smith, and also shares a son and daughter with socialite and actress Grace Hightower.
Other famous faces have welcomed children later in life, including former chief executive of the Formula One Group Bernie Ecclestone, former Channel 4 News broadcaster Jon Snow, singer Billy Joel and Rolling Stones singer Sir Mick Jagger.
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