Taylor Swift and Calvin Harris Step Out In NYC -- What We Know About Their Relationship

Get all the details of their date night in New York City.

Last night, after enjoying dinner at L'asso in Manhattan, they were photographed holding hands en route back to her apartment.

"They seem pretty happy together," a source told ABC News.

At the restaurant, the two shared two gluten-free pizzas: one with prosciutto and scallions and a simple tomato pie, an onlooker said. Swift, 25, sipped a glass of wine.

"She looked happier than her normal, happy self," the first source said. "She seemed to have a glow about her."