While the pair haven't officially confirmed their romantic relationship, the actors showed some PDA during the star-studded evening.
Rooney Mara and Joaquin Phoenix made their love known during the closing ceremony of the 70th annual Cannes Film Festival on Sunday.
While Mara, 30, and Phoenix, 42, have never publicly commented on the nature of their relationship, it was clear the celebrated thespians -- who co-star in the upcoming drama Mary Magdalene -- have a super sweet connection.
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The pair sat beside each other during the star-studded closing ceremony, and were seen sweetly hugging as the event began.
Phoenix was also seen placing his hand on Mara's leg as it was announced that he'd won the award for Best Actor for Lynne Ramsay's thriller You Were Never Really Here.
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The pair embraced as Phoenix reacted with legitimate surprise after being named the winner of the coveted award.
Mara was a vision in white, rocking an angelic, bead-embellished Dior gown with three-quart sleeves and a collar, while Phoenix rocked a crisp tuxedo that he paired with black converse sneakers.
The actor apologized for his less-than-formal footwear as he took to the stage to accept his award from actress and Cannes jury member Jessica Chastain, explaining that the win was "totally unexpected."
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The pair were spotted leaving the event together, holding hands, and driving off in the same car.
Phoenix and Mara previously appeared together in the 2013 dramedy Her.
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