The baby, Gisele's second with husband Tom Brady, is a girl.
Here's the Facebook message:
We feel so lucky to have been able to experience the miracle of birth once again and are forever grateful for the opportunity to be the parents of another little angel. Vivian Lake was born at home on December 5. She is healthy and full of life.
Thank you all for your support and well wishes. We wish you and your families many blessings.
The name Vivian actually means "full of life," so Gisele is either a clever wordsmith or a boring writer with no new insights about her baby other than that it is alive. The name Lake refers to "a large body of standing water surrounded by land," and is generally not a name.
Gisele's first son with Tom Brady, Benjamin Rein, was born on December 8, 2009, so he and his sister will grow up to have lots of fights over birthday party scheduling.
Tom Brady also has a five year old son, John, from a previous relationship with actress Bridget Moynahan.
While months of pictures of Gisele's growing stomach led many to speculate that she was pregnant, the model has yet to publicly confirm her pregnancy.