Fox News Flash top entertainment and celebrity headlines are here. The couple have named their new baby boy after Phoenix's late brother, River, who tragically passed away in 1993 aged just 23 years old.
Reps for Joaquin and Rooney did not immediately respond to Access Hollywood's request for comment.
According to global portals, the news was shared by Russian filmmaker Victor Kossakovsky during a Q&A at the 2020 Zurich Film Festival on Sunday, post the screening of his documentary "Gunda", executive produced by Pheonix.
The Girl with the Dragon Tattoo star and the Oscar-winning actor welcomed their first child together, according to Russian filmmaker Victor Kossakovsky-and we've already got a name.
"He just got a baby, by the way, his name was...a handsome son named River, so he can not promote it now", the director revealed.
"He just got a baby, by the way, his name was ... a lovely son called River, so he can not promote it now", the filmmaker said, according to video posted to social media from the event. They quoted a source as saying: "Rooney is about six months along".
Previously, the proud parent duo have co-starred in films Don't Worry, He Won't Get Far on Foot and Mary Magdalene.
Joaquin Phoenix attends the EE British Academy Film Awards 2020 After Party at The Grosvenor House Hotel on February 2, 2020 in London. By May of 2019, Mara was spotted with a massive ring on that finger, leading to reports that the couple had gotten engaged. However, the notoriously private couple has not publicly announced the birth of their son.