Rooney Mara and Joaquin Phoenix have welcomed their first child together — a son named River after Phoenix’s late brother, who died in 1993.

The news was confirmed by Russian director Victor Kossakovsky at the 2020 Zurich Film Festival on Sunday. The director had worked with Joaquin Phoenix, who served as executive producer on his film, Gunda, a documentary following the lives of farm animals.

“He just got a baby by the way,” Kossakovsky said on stage at the film festival. “A beautiful son called River.”

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Victor Kossakovsky, Regisseur von "Gunda" über das Zustandekommen der Zusammenarbeit mit Oscar-Preisträger @joaquinlphoenix der den Film mitproduziert hat. Ich wünsche ihm und @rooney.mara alles Gute und viel Freude mit ihrem ersten Sohn River!☺️💜☀️ Gunda ist ein Säuli, dass der Zuschauer von Geburt ihrer Babys bis zur Entreissung zusieht und hoffentlich ein paar Menschen ein Licht aufgeht, wenn sie die traurige Gunda ihre Babys suchen sehen und ihr Weinen hören! Animal are friends not food👉🏻go vegan! . . . . #filmblogger #swissgirl #swissbloggers #lifestyleblogger_de #lifestyleblogger_ch #blogger_de #blogger_ch #zürich🇨🇭 #zürilove #wipkingen #selfcare #somethingwonderful #filmkritik #moviereview #kinotipp #govegan #vegan #animalsarefriendsnotfood #interview #wearestrongertogether #diabetes #t1dlookslikeme #joaquinphoenix #victorkossakovsky

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Mara and Phoenix had worked together on the 2013 movie Her, but didn’t begin dating publicly until 2017, when they appeared for the first time as a couple on the red carpet at the Cannes Film Festival. They were engaged in 2019, and in May it was reported on rumors that The Girl With The Dragon Tattoo star was pregnant.

The couple seems to keep their relationship on the down-low, but after winning the Tribute Actor Award at the Toronto International Film Festival last September Phoenix said, “One last thing — somewhere here, I don’t know where, is a filthy dragon, and I want to rip its wings off and fasten a blanket and sleep with it forever,” he said of his fiancé. “I love you. Thank you.”