Blue Bloods star Marisa Ramirez is pregnant with her first child.

The actress, who is due to give birth in May (16), confesses her pregnancy was not planned.

"This was a complete surprise," she tells People.com. "Some mornings I wake up and forget I'm pregnant! It just seems like it was meant to be - a happy surprise."

"I get to experience this anticipation and excitement of meeting a child that will change my world forever and who will bring us so much joy," she continues. "Sometimes it definitely feels like a panic, but I know it's layered with excitement."

Ramirez has been flooded with baby advice from her castmates on the hit police drama, and she is particularly grateful for the support of co-star and onscreen partner, Donnie Wahlberg.

"Donnie has known (I am pregnant) for a while," the mother-to-be reveals. "He did a little happy dance when I told him and he's been extremely supportive and sweet.

"It gives me such a warm and fuzzy feeling knowing that my Blue Bloods family is there to help me transition into this new chapter of my life."

The father of Ramirez's child has yet to be revealed. She divorced Nathan Lavezoli in 2011 after nine years of marriage.