The baby was 8 pounds, 5 ounces when he was born Tuesday night, UsMagazine.com reported Wednesday.
Hart married Course of Nature front man Mark Wilkerson in 2003. They are already the parents of Braydon, 4, and Mason, 6.
Hart is best known for her work on TV's "Melissa & Joey," "Clarissa Explains It All" and "Sabrina, the Teenage Witch."
Celebrity Breakups and divorces of 2014 [PHOTOS]