Teen Mom 2 Baby: How Chelsea's Children Reacted To Their Sibling-On-The-Way

Find out what Aubree, Watson and Layne think of kiddo number four

Teen Mom 2's Chelsea Houska is pregnant with her fourth (!) bundle of joy (her third little one with husband Cole DeBoer). The MTV kiddos will now outnumber their parents 2-1!

And speaking of the DeBoer children, how does Chelsea's first mini-me feel about the upcoming addition to the clan?

"Aubree's excited!" Chelsea, who will soon be tied with Kailyn Lowry for being mom to the most munchkins on the long-running series, revealed to MTV News. "She knew we wanted one more, so it wasn’t a huge surprise."

But Aubree's siblings don't quite get all of the excitement in the DeBoer household about the petite princess.

“They will both say there's a baby in my tummy, but I don't think they understand what that means at all," Chelsea explained about Watson, three, and Layne, who's almost two.

Be sure to stay with MTV News for all Baby DeBoer updates -- and catch Chelsea, Cole, Aubree, Watson and Layne on the brand-new season of Teen Mom 2 premiering on Tuesday at 8/7c (watch a preview below!)