Well, looks like these two are certainly going strong.
Joining the Oscar-winning duo was Charlize's adorable 2-year-old son, Jackson, who appears to have bonded with Penn in recent months, as the trio has been spotted spending time together on numerous occasions.
Both Charlize and Sean looked comfy and casual during their afternoon stroll. The 38-year-old South African beauty was dressed down in a striped T-shirt, boyfriend jeans, tennis shoes and black shades, while her 53-year-old man wore a green and pink flannel and basic pants.
Two dogs, one brown and white and the other gray, also joined the trio on their outing, during which time the couple shared a number of warm embraces (and kept a watchful eye over little Jackson!) as they enjoyed the beautiful setting.
This isn't the first time the precious trio has been spotted hanging out in Malibu, where Penn owns a home and spends much of his time. The Mystic River star was seen bonding with his girlfriend's son on the beach just last month, where the couple and little Jackson enjoyed a fun-filled day together while seeming like the image of the picture-perfect family.
The A-listers were first romantically linked just after the New Year when they were spotted returning to Los Angeles after spending the holidays in Hawaii together.
Shortly after, they were seen grabbing coffee in Malibu, attending a screening of The Wolf of Wall Street and, according to a source, their relationship is seemingly on the fast track (which is fairly obviously, based on the ample amount of time they've been spending together).
"They are spending night after night together and moving very fast," a source exclusively told E! News after the two first coupled up. "It seems like it's getting serious and that they can't get enough of each other." (Reps for Penn and Theron have declined to comment on their relationship status.)
The pair most recently walked their first red carpet together, attending the Fame and Philanthropy post-Oscar party. And while Penn did not accompany Theron to the 2014 Academy Awards, where the blond beauty served as a presenter, an eyewitness told E! News "they seemed happy and at peace" inside the bash.
Dare we say Sean is smitten?