Actors Blake Lively, 27, and Ryan Reynolds, 37, welcomed their first child in December, People magazine reports.
The baby -- whose gender has not been revealed -- was born prematurely, but is now doing well.
The child was born near the couple's home in Bedford in Westchester County.
After news of Lively's pregnancy was announced last year, "Green Lantern" star Reynolds told People: "I'm just excited about having a buddy. For a lot of new dads, you tend to dwell on the mistakes you don't want to make. I'm at that stage still where I'm focused primarily on being open and understanding and leaving a lot of room for error."