Actress, author and lifestyle blogger Tori Spelling and her husband, Dean McDermott, a star of the Canadian crime-drama anthology “Slasher,” are expecting their fifth child together.

“It was a total surprise,” Spelling, 43, told People magazine in online excerpts Wednesday from the upcoming issue, being published Friday. “But we always wanted a big family,” she added. “I’m really excited.”

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The couple, who married in May 2006 on the South Pacific island of Fiji, are parents to Liam, 9, Stella, 8, Hattie, who turns 5 on Monday, and Finn, 4. McDermott, 49, also has a son, Jack, born October 1998, from his 13-year marriage to Canadian actress and TV host Mary Jo Eustace.

“Dean was saying, ‘We just got Finn out of diapers; I thought we were in the clear!’ ” Spelling said jokingly. “For the first time this year, they’re all in school. So it’s like, wow. We’re basically starting over.”

Nonetheless, she said, “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.”

Spelling, best known for the 1990-2000 teen drama “Beverly Hills, 90210” and the cult-favorite TV-movie “Mother, May I Sleep with Danger?” (1996), is the daughter of the late TV producer Aaron Spelling. She and McDermott have starred in reality shows including “True Tori” and “Tori & Dean: Cabin Fever.”