Actors Joaquin Phoenix and Rooney Mara are officially proud parents. According to Peoplethe Her costars have welcomed a baby boy together.

Russian filmmaker Victor Kossakovsky confirmed news of the pair’s baby during a press conference at the Zurich Film Festival for his and Phoenix’s upcoming documentary, Gunda. When explaining why Phoenix was not in attendance, Kossakovsky revealed that Phoenix and Mara had welcomed their son, following previous reports that the two were expecting a child together.

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“He just got a baby by the way, his name was … a beautiful son called River, so he cannot promote it now,” said Kossakovsky during the conference. The baby’s name pays homage to Phoenix’s late brother, River Phoenix, the acclaimed young actor who died in 1993 at the age of just 23.

Phoenix and Mara first met on the set of their 2013 film, Her, and confirmed their ultra-private romance with a joint appearance at the Cannes Film Festival in 2017. Per People, the pair got engaged last year, as Mara was photographed wearing a large diamond ring on her left hand. The couple also attended both the Golden Globes and the Academy Awards together this year, with Phoenix scoring top prizes for his starring role in Todd Phillips’s Joker film.

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During the actor’s acceptance speech at last year’s Toronto International Film Festival, he thanked both his late brother and his fiancée for continuing to inspire him in and out of his career.

“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,” said Phoenix during his speech, seemingly referencing his partner’s breakout film, The Girl with the Dragon Tattoo. “I love you. Thank you.”

This article originally appeared on Harper’s BAZAAR US.

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