The celebrated actor announced that he and Chen had welcomed a child earlier this month.
De Niro, 79, and Chen hit up the Vanity Fair x Prada party on Saturday night at the Hotel du Cap-Eden-Roc in France and made a splash in matching black ensembles.
The two-time Oscar winner rocked a classic black tux with a white shirt and dark tie, while Chen rocked a black zippered jacket over a black top and dark shades.
The party outing came hours after De Niro and Chen walked the carpet at the Cannes Film Fest premiere of his new film, director Martin Scorsese's Killers of the Flower Moon -- in which he stars opposite Leonardo Di Caprio.
De Niro rocked the same tux at the stylish premiere, while Chen shimmered in a glimmering black sequined gown and the same dark shades.
De Niro's hotly anticipated new project took the festival by storm and reportedly earned a nine-minute standing ovation after its screening on Saturday, which bodes well for the long-awaited period drama.
Meanwhile, the couple's Cannes appearance comes a few weeks after De Niro first revealed that he'd recently welcomed his 7th child. A few days later, on CBS Mornings, Gayle King shared the exclusive first photo of De Niro and Tiffany Chen's daughter.
The baby girl's name is Gia Virginia Chen-De Niro, and according to King, she was born on April 6 and weighed 8 lbs., 6 oz. Along with the announcement was a sweet photo of little Virginia -- named after De Niro's mother -- who is seen wearing a pink onesie as she gazes into the camera while being held up by her dad.
De Niro told King that he and Chen are "over the moon" about their little bundle of joy, who was planned and "brought here by love."
On May 9, the Oscar-winning actor walked the red carpet at the New York City premiere of About My Father at the SVA Theatre and addressed how dad life with a new baby has been.
"It's great!" he told ET.
De Niro shares his adult children Drena, 51, and Raphael, 46, with ex-wife Diahnne Abbott, as well as 27-year-old twin sons, Aaron and Julian, with former girlfriend Toukie Smith. He also shares son Elliot, 25, and daughter Helen Grace, 11, with ex-wife Grace Hightower.
De Niro and Hightower filed for divorce in late 2018 after 21 years of marriage.