Mira Sorvino is now a mom of three, and she's opening up about her third pregnancy, including plans to write a book about the experience!

Mira and hubby Christopher Backus welcomed a baby boy on June 22 at 12:10 a.m., named Holden Paul Terry Backus. Mira says that her son's middle names are for both of his grandfathers. The baby boy, who weighed in at 8 lbs., 12 oz., was born following a pregnancy that involved life-threatening complications to mother and child, but a rep for Sorvino tells ET that the whole family is now healthy and happy at home. Holden joins big sister Mattea, 4, and big brother Johnny, 3.

Mira tells ET that she developed severe complications during her pregnancy that included a condition called placenta previa, as well as a blood clot that could have led to a pulmonary embolism. Sorvino spent nine weeks in the hospital during her pregnancy, and tells ET that the separation from her two older children was difficult: "Prior to this hospital stay, I had only ever spent one night away from Johnny and Mattea."

Happily, little Holden was delivered healthy following a long and intense labor that almost led to a c-section. "It was amazing," Mira says, "As soon as they placed him in my arms, I knew it had all been worth it. He is my miracle baby; with everything that threatened this pregnancy and both of our lives, he came out of it completely unscathed: perfectly healthy, beautiful and wonderful!"

Mira says that her husband Chris was "her rock" during the experience, and that she "couldn't have done it without him."

"Chris was a true hero while I was in the hospital, taking care of every aspect of our lives and attending to all of the kids' needs during a truly difficult time for all of us," Mira says of her husband.

Mira says that Holden "seems like a very old soul" with a "darling personality." She says that her two older children love their new brother, and that they make up songs to sing to him.

The happy parents say, "We are overjoyed to bring our beautiful healthy son home to his brother and sister. We are blessed to have a home filled with so much love."

A book about the experience is in the works, and Mira says, "I find that putting pen to paper helps me remember more details about the experience and sort through my feelings and the way it has changed me, I believe, for the better."