Tori Spelling once played notorious virgin Donna Martin on 90210, but now she's anything but. Spelling, 38, and husband Dean McDermott, 44, are welcoming their third child — a girl named Hattie. The new baby joins brother Liam, 4, and big sis Stella, 3.

The happy couple announced the birth on Twitter. "Our family's so happy 2 announce tht 10/10/11 R baby girl Hattie Margaret McDermott was born at 7:08am!" they tweeted on Tuesday. The birth had been expected to take place a week later, but Hattie was ready to come out.

All the behind-the-scenes action will be yours when the pair's reality show, Tori & Dean: Home Sweet Hollywood, premieres November 29 on Oxygen.