Tori Spelling Keeping Baby #3's Sex a Surprise

Tori Spelling just announced her third pregnancy – and this time around, she wants to do things differently.

The Tori & Dean: sTORIbook Weddings star says she and hubby Dean McDermott want to keep the sex of their baby a surprise.

"We've been blessed with a boy and girl already, so this time we've decided to do it the traditional way and not find out the sex," Spelling, 37, tells PEOPLE.

Already mom to son Liam, 4, and daughter Stella, 2, the reality star says her new addition will be joining an already boisterous brood.

"They are best friends but they are at that age where there's that love-hate relationship," Spelling told PEOPLE at the GLAAD Media Awards in Los Angeles recently. "[Liam] beats [Stella] up, and she just adores him."

But by nightfall, all is forgotten. "They just started sleeping together," Spelling said. "That's their new thing. They want to sleep in the same room."

Credit: PEOPLE (Sara Durham Wilson)

Tori Spelling: I'm Pregnant With My Third Child!

Tori Spelling and hubby Dean McDermott are expecting their third child! The actress and reality star, 37, announced her baby news via Twitter Monday

"I know there's been a lot of speculation, so I wanted everyone to hear from me. . .it's official. . . Dean & I are PREGNANT!"

Married since 2006, Spelling and McDermott, 44, have two children together: son Liam, 4, and daughter Stella, 2.

The Beverly Hills, 90210 vet concealed her growing baby bump in NYC on Monday, where she and McDermott were promoting their new Oxygen reality series sTORIbook Weddings. The famous couple were coy with Us Magazine about expanding their brood.

"We definitely [want more kids]," Spelling admitted.

"We want a couple more," McDermott added. So do little Liam and Stella, who "want [a younger sibling] really bad," McDermott said. "They love babies!"

"They ask us every day!" Spelling added. "It's so funny!

Best part about parenthood? "Every second!" Spelling cooed.

"It's ever-changing," her hubby added.

"It's challenging, but every second is amazing," Spelling told Us in August 2010: "I'm passionate about everything in my life. Obviously my family and my kids are my priority. I want to be that stay-at-home mom, but I want to build an empire at the same time."

Credit: Us Magazine