This will be the couple's first child. McDermott has two children — Lola and Jack — with his ex-wife, Mary Jo Eustace. McDermott and Spelling tied the knot at a private ceremony in Fiji in May.
In Touch magazine reported the pregnancy in its Sept. 11 issue, saying that the actress would go public with the news at the three-month mark.
"She doesn't want to announce it yet, but she and Dean are excited," an insider told the magazine. "They don't want the announcement to be overshadowed by everything that's going on with her family, but they are very, very happy."
The actress, the daughter of TV producer Aaron Spelling who died in June at age 83, has reportedly been feuding with her mother, Candy, over her father's multimillion-dollar estate.
By Amy Bonawitz