Pitt and Theron, 43, met properly last year on a commercial shoot.
They shot an ad for watch brand Breitling last year with Adam Driver. The company released a sneak peek at the campaign back in September on their Facebook page.
“About six months ago, they did a shoot together. So they have spent time together,” a source dished to PEOPLE.
“But anything that may have happened beyond that remains to be seen.”
On Jan. 20, the U.K.’s Sun newspaper claimed that Pitt and Theron had struck up a romance over Christmas.
Neither star has commented.