Joaquin Phoenix, Rooney Mara Welcome Baby Boy, Name Child After 'Joker' Star's Late Brother

Joaquin Phoenix and Rooney Mara welcomed their first child together, a son whom they named River.

Phoenix and Mara usually keep their relationship private, but in May, a source confirmed to Page Six that the couple was expecting their first child together. Now, Russian filmmaker Victor Kossakovsky has announced during a Q&A at the 2020 Zurich Film Festival that their baby has already arrived.

"He just got a baby, by the way, his name was … a beautiful son called River, so he cannot promote it now," the director said Sunday while explaining why Phoenix was not present during the screening of "Gunda," a documentary that the actor executive produced.

Us Weekly noted that the name the couple picked out came from his late older brother, River Phoenix, who starred in films such as "Stand By Me" and "The Thing Called Love." He died in 1993 at the age of 23 due to drug overdose.

An insider told the outlet in May that Mara was already six months along at the time and Phoenix had been accompanying her to appointments.

In May last year, news of Phoenix and Mara's engagement made headlines after she was spotted sporting a diamond ring while running errands in Los Angeles. Four months later, Phoenix confirmed that they live together in California's Hollywood Hills.

The two kept their romance private for a couple of months before they made their red carpet debut as a couple at the Cannes Film Festival's closing ceremony. An insider told Us Weekly that the lovers were very in love, and this was evident in Phoenix’s speeches when he received his awards.

"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. I love you. Thank you," Phoenix said while accepting his People’s Choice award at the Toronto International Film Festival in September 2019.

He also expressed his love for Mara when he accepted his best actor trophy for "Joker" at the Golden Globes in the same year.

In an interview with Vanity Fair, Phoenix revealed that Mara was the only woman he had ever looked up on the internet.