Spelling, 38, married actor Dean McDermott, 45, in 2006. She gave birth to daughter Hattie Margaret five months ago. Hattie has a brother Liam, 5, and sister Stella, 3.
"Dean, Liam, Stella, Hattie, and I are beyond thrilled to announce that another little McDermott is on the way! We feel truly blessed that another angel has found us. Love, Tori xoxo," Spelling said Friday on her Web site.
She did not say what the baby's gender is or when he or she is expected to be born.
Spelling and McDermott have appeared in the reality TV shows "Tori & Dean: sTORIbook Weddings," "Tori & Dean: Inn Love" and "Tori & Dean: Home Sweet Hollywood."