Chelsea Houska will soon welcome a "sweet baby girl" -- and the Teen Mom 2 cast member is showing the first belly shot of the bundle of joy. Hello, "wittle bump"!

Before sharing the Twitpic above -- and stating that this pregnancy has been a "breeze so far" -- Chelsea expressed her appreciation for the outpouring of support following the milestone announcement:

This little lady will join big sister Aubree -- who is so excited to share the news with her schoolmates and "yell it down the hallways!" -- and soon-to-be middle man Watson Cole. Chelsea also revealed she is "about four months" and the baby is due in September (but is prepared for the munchkin to arrive in August because her first two kiddos came a "couple weeks early.")

Stay with MTV News as Chelsea and Cole get ready to become a DeBoer party of five!