"Tori and Dean wanted to keep the baby's sex a secret especially from the kids who tend to talk about everything going on in the house," says a source. "So they were really careful."
However, Tori recently slipped while speaking about the pregnancy and called the baby "he," and her kids were quick to notice.
"With the cat already out of the bag, the couple is now telling a few close friends and family what they are expecting," the source said.
Tori, 43, and Dean, 50, are already parents to Liam, 9, Stella, 8, Hattie, 5, and Finn, 4.
"The couple have not chosen a name yet, saying they want to wait and see what the baby looks like before tagging it with a moniker," the source added. "But she had been talking about including her father's name Aaron as part of the baby's name."
Tori is reportedly nervous about the delivery, considering the complications she had while delivering Finn four years ago -- she suffered from placenta previa, a condition in which the placenta blocks the cervix. Her life was at risk.
"But Dean is by her side and she feels safe in the hands of her doctors," the source said, "so everything is a go - and the entire family is ready to welcome the new baby boy into the family."
In October, Tori announced that she was pregnant, something that surprised even her.
"It was a total surprise But we always wanted a big family. I'm really excited," she told People magazine at the time. "This baby happened at the best time. Nothing is ever perfect, but I'm so madly in love with my husband and with our kids. The idea of adding to that is such a blessing."