Anna Duggar pregnant

The family that just keeps growing... is growing again!

Anna and Josh Duggar are expecting baby number four. Anna shared the announcement on her Twitter feed on Tuesday night, posting, "We are so excited to announce...we're pregnant!"

She used a few hashtags to punctuate the exciting message, including "BlessingfromTheLord" in a nod to their well-known faith, "#19Kids" as a reference to the family's TLC show 19 Kids and Counting, and a third hashtag that suggests the pair are taking after the family matriarch and patriarch: "#4andcounting."

Just how many children will they have in the end? It's anyone's guess, but it's not their top concern. "It's really not about the number of children you have, but how well are you doing with the children that God has given you," Josh told E! News recently. "We're really just going to take it one at a time. I don't think you can say we're going to set out and say we're going to have five kids or four or three. We have no control over that. God has the control."

The news comes on the heels of pregnancy news from Jill Duggar and Derick Dillard, who conceived almost immediately following their June wedding. They, too, would be happy to have as many kids as possible: Jill told ABC News last year, "Both of us want as many kids as God will give us. My parents have kept popping them out so we'll see how [our] fertility is!"

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Photo courtesy of Twitter/Anna_Duggar