Teen Mom 2's Chelsea Reflects On Her Unforgettable Pregnancy Reveal

Plus, the soon-to-be mama of two shares how Aubree is preparing for her baby brother

Chelsea is almost ready to welcome Baby DeBoer (Valentine's Day is her due date!) -- but during tonight's brand-new Teen Mom 2 episode, the soon-to-be mother of two and hubby Cole excitedly disclosed the pregnancy news to their MTV crew (a wonderful benefit of breaking the fourth wall) and to Aubree (in a heartwarming reveal).

Getting to Chelsea's mini-me in a minute, but keeping this life-changing development from her producer Mandi -- who was visibly emotional when she found out the esthetician was avec child -- wasn't easy.

"It was hard for me because I'm used to telling her everything that goes on. I'm supposed to keep her in the know," Chelsea confessed to MTV News. "But I couldn't even text her because if I had, I would have told her. So she thought I was mad at her, and she asked me what was going on. And then she came into the house, and finally I could tell her I was pregnant."

And since Aubree learned of her sibling (what a moment!), what excites the six-year-old most about having another kiddo in the household?

"To have someone to play with and take care of," the 25-year-old explained. "She's been an only child -- she gets a bit bored just hanging out with me and Cole. We're not as fun as younger kids, so I think she's excited to have a little friend. She even wants a crib in her bedroom so she can get up in the night with him! I said I would take her up on that offer," Chelsea added with a laugh. Big sister extraordinaire!

Be sure to keep watching Teen Mom 2 every Monday at 9/8c as Chelsea and Cole's journey toward welcoming their son continues -- and stay with MTV News as we get closer and closer to the big arrival in the next few weeks!