The 19 Kids & Counting stars will welcome their latest addition from their new city, Washington, D.C.

Another happy addition – No. 4 – is on the way for 19 Kids & Counting stars Anna and Josh Duggar.

“I’m nine weeks pregnant, and having a lot of morning sickness,” Anna says in a first-look promotional video from TLC, sitting on a couch with her husband and surrounded by her three children, daughter Mackynzie, 5, son Michael, 3½, and son Marcus, 18 months.

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Anna shared the couple’s big news via Twitter on Tuesday, noting, “We are so excited to announce we’re pregnant.” She added the hashtags #4andcounting and #BlessingfromTheLord.

The news caps an abundant year for the deeply religious family after the wedding of Anna’s sister Jill to Derick Dillard in June, and their announcement two months later that they were expecting – and it’s a boy.

The couple – who wed in 2008 – now live in Washington, D.C., where Josh is a lobbyist for the highly conservative and controversial Family Research Council, according to the Washington Post.

“Having a baby in D.C. is totally different,” Josh says, recalling the couple’s early lives together in Arkansas where much of the Duggar clan resides.