Tori Spelling can't wait for the arrival of her fourth child with husband Dean McDermott -- and she's not the only one!

"I'm excited about the baby!" the couple's firstborn son, Liam, 5, told Us Weekly in Burbank, Calif. August 29. The happy family (sans daughter Hattie, 10 months) teamed up to participate in Lunchables' and Never Be Bored Again's campaign at the Boys and Girls club of Burbank.

PHOTOS: Meet Tori Spelling and Dean McDermott's daughter Hattie!

"They are excited!" Spelling, 38, echoed. "I got pregnant so quickly after I had Hattie that I think they're just like, 'Oh, Mom's constantly in a state of pregnancy.' They say they're going to be excited when I'm not pregnant anymore so I can have pillow fights again with them. That's their big thing."

Spelling -- also mom to daughter Stella, 4 -- said this pregnancy is "probably going to be my last." Knowing that it's almost over makes the experience bittersweet, the Beverly Hills, 90210 alum admitted.

PHOTOS: Tori Spelling's life in the public eye

"I couldn't be happier that I'm finally at the end and I get to meet baby so soon, but I actually love being pregnant, so if it is my last, I'll be sad never to be pregnant again," the Craft Wars host told Us. "It'll have been a  precious moment in time and it'll be over with, so it is sad."

"When you realize one phase is completely over, it's hard," Spelling added.

True to form, Spelling has been keeping busy -- and getting crafty! -- in the months leading up to her due date. "We made a rug together for the baby's nursery. We go to estate sales and yard sales all the time; We were at a  yard sale a few weeks ago and I saw these amazing placemats -- like really  heavy yarn ones, they're pretty thick -- and I was like, 'That would be perfect for the baby's nursery!' So we actually got a piece of canvas, cut it out and we glued the placemats on there and made an area rug for the baby."

VIDEO: Tori Spelling stuffs steak down her tank top

With the help of her Liam, Stella and her stepson Jack, 13, the famous blonde said she's ready to bring her baby home. "We're a big crafting family," Spelling told Us. "We've been doing a lot of DIY stuff for the nursery and making stuff."

Spelling and McDermott, 45, tied the knot in a private ceremony in Wakaya, Fiji in May 2006.

This article originally appeared on Tori Spelling's Son Liam McDermott, 5: "I'm Excited About the Baby!"