Tori Spelling and husband Dean McDermott have welcomed their third child into the world.

"Our family's so happy 2 announce [that on] 10/10/11, [our] baby girl Hattie Margaret McDermott was born at 7:08AM! Xoxo," Spelling wrote on her Twitter account Tuesday.

The Tori & Dean stars had announced the pregnancy in April via Twitter as well but decided to keep the sex of the baby a mystery.

Hattie is the couple's second daughter. Three-year-old Stella Doreen McDermott was born in June 2008, while 4-year-old Liam Aaron McDermott, Hattie and Stella's older brother, was welcomed into the family in March 2007.

Liam was born a week before the first-season premiere of Spelling and McDermott's Tori & Dean: Inn Love Oxygen reality series, and Spelling coincidentally gave birth to Stella a week before the third-season debut of Tori & Dean: Home Sweet Hollywood.

Tori & Dean: Home Sweet Hollywood viewers will get their first peak at Hattie during the show's sixth-season premiere, which will air Tuesday, November 29 at 10PM ET/PT and include a special live peek into the family's home.