The low-key pair have been spending time together over the past few months and appear to be getting more serious about their relationship.
"They're really into each other," says a source. "They're a really good match and just enjoying it all right now."
On Thursday, Phillippe, 36, stopped by to see Seyfried, 26, on the set of her new film, Now. After enjoying a bite to eat the two took a break and went for a walk.
The next day, they shared a late morning breakfast with pals at the Los Angeles restaurant Joan's On Third. Sitting next to one another, "They were really cute," says an onlooker. "The two of them smiled the whole time."