Per People magazine, citing a source, the stars were leaving Havana, Cuba, on Saturday evening, and spotted making out in the airport before they boarded their private jet.
“They are definitely dating,” the source added.
The news comes after Affleck, 47, and de Armas, 31, were recently seen dining in Havana, where they stopped and smiled alongside fans and restaurant employees, pictures obtained by the Daily Mail show.
The stars reportedly became close while filming the Adrian Lyne-directed drama "Deep Water," which wrapped filming weeks ago. According to the outlet, the two stars were spotted in more than one restaurant together and continued their getaway by leisurely shopping and walking around the streets of Havana.
In one photo obtained by the outlet, the actor appeared to have his arm wrapped over de Armas' shoulder as the duo was surrounded by nearly a dozen ecstatic fans. One onlooker told Us Weekly the two were also spotted having some fun inside a T-shirt shop.
"It was just the two of them and their driver. Ben happily took photos with fans. Ben was in a very happy mood, making funny faces in selfies with fans," said the eyewitness.
De Armas is a native of Cuba and studied theater in Havana, according to her IMDb page.
Affleck was previously married to Jennifer Garner – with whom he shares three children – for 10 years. Following his split with Garner, 47, Affleck was linked to "Saturday Night Live" producer Lindsay Shookus and model Shauna Sexton.
De Armas was reportedly married to actor Marc Clotet from 2011 until 2013.
Reps for Affleck and de Armas did not immediately respond to Fox News' request for comment.
Fox News' Melissa Roberto contributed to this report