It's official ... Catelynn Lowell is pregnant!

The "Teen Mom" star took to Instagram Wednesday to share a snapshot of her growing baby bump.

"#it'soffical #4months," she wrote along with the cute candid. Fiance and baby daddy Tyler Baltierra posted the same photo, in color (above).

In the pic, the expecting star is looking away from the camera as she cradles her blossoming belly.  

Lowell's mother, April Stotts, commented on her daughter's pregnancy news back in May, but this is the first official confirmation from the MTV reality starlet.

"She called to ask me about a pregnancy test and if I thought she was pregnant," the grandmother-to-be told Us Weekly. "So I made her send me a picture and I told her, 'I believe you are, you should go get a couple more and take a couple more.'"

"She was crying when she knew for sure and so I was like, 'Are you happy? Are you upset?' And she was like I’m happy!'" her mom added.

The is the second child for Catelynn and Tyler. The pair put their first daughter, Carly, up for adoption -- but still have a relationship with her adoptive parents.

Congrats to the cute couple!

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