Inside Rooney Mara and Joaquin Phoenix’s Private Romance, from Biblical Costars to Cannes Twosome

Rooney Mara and Joaquin Phoenix are finally making things official, but their relationship has always been low-key.

The long-rumored couple stepped out for their first public event together at the Cannes Film Festival closing ceremony on Sunday, where they were spotted intimately chatting and warmly embracing after Phoenix won the best actor award for his performance in the drama You Were Never Really Here. They later left the gala hand in hand.

They were first rumored to be dating in early January when Page Six reported they had struck up a romance on the set of their biblical tale Mary Magdalene, where Mara plays the titular character and Phoenix stars as Jesus. The two were reportedly seen spending time together on and off set while filming last fall, including an outing on their Italian hotel’s balcony where they were seen hanging out while smoking.

Once back in the U.S., Mara, 32, and Phoenix, 42, were spotted leaving a detox spa in California just days after reports of a rumored romance broke. The private couple have only stepped out together a handful of times since then, including a grocery run shortly after they were first linked together. The two famously reclusive stars were seen smiling at each other as Mara carried grocery bags to the car.

Joaquin Phoenix and Rooney Mara leaving after having breakfast together in Studio City. (Photo: INSTARimages.com)

Three weeks later, the two made their relationship awards-ceremony official when they jointly attended the Cannes Film Festival’s closing-night ceremony.

They were also spotted during a pre-Cannes breakfast outing in California in early May, where Mara matched Phoenix’s blue-striped sweater with her own yellow-and-brown-striped one.

Joaquin Phoenix and Rooney Mara were hand in hand at the closing ceremony. (Photo: Starface/Splash News)

Joaquin Phoenix and  Rooney Mara were very close at the closing ceremony of the 70th Cannes Film Festival. (Photo: ALBERTO PIZZOLI/AFP/Getty Images)

Phoenix looked shocked as his name was called as the best actor winner, with Mara sweetly urging him to head to the stage to pick up the award as they warmly embraced.

“They were talking to one another nonstop,” a source tells PEOPLE of the two during the ceremony. “Small talk between them. Then they went for their car and he’s holding her hand like it was unconscious. Like it fits. They seem a totally natural and easy couple.”