The 26-year-old "Counting On" star is expecting her second child, a daughter, with her husband, Jeremy Vuolo.
Duggar shared the news Thursday on Instagram alongside a photo of herself cradling her baby bump.
"We are so excited to announce that we're expecting a little girl this November! Jeremy and I both guessed it was a girl, just a gut feeling we had. And we couldn't be happier," she captioned the post.
Duggar and Vuolo already have a 22-month-old daughter, Felicity Nicole.
In her post, Duggar, one of Jim Bob and Michelle Duggar's 19 children, reflected on the special bond she shares with her own sisters.
"The bond that sisters share is unique, and one I cherish every day. After all these years, they're still my best friends! I'm glad God's giving that gift for Felicity to enjoy," she said.
"As for me and Jeremy, we'll definitely have our hands full! But there's nothing else we'd rather carry."
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Vuolo confirmed the news in a post on his own account.
"And then there were four... Felicity's recruited a little sister to join her squad! Recently, she's been practicing her big-sistering on dolls, cradling and shushing them to sleep. Pretty soon, she'll be holding a real baby. But she's ready, and so are we," he wrote.
"Life is beautiful! We are praising God for this precious little gift," he added.
On the TLCme website, Duggar and Vuolo shared for the first time that they previously experienced a miscarriage.
"That was very difficult and definitely a trial for us," Vuolo said.
The couple will show their emotional journey and move to Los Angeles in the new season of "Counting On," which premieres June 30 on TLC.
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