"It's a boy!" Tori captioned a Sunday Instagram photo of Zach and herself celebrating at a gender-reveal party.
"Zach and I are so excited to finally find out what we are having! We were so blessed to be able to share the moment with such close friends and family! Things are getting real at the Roloff household!"
Zach shared a similar picture, writing on social media that he's "super stoked" about having a son.
According to a TLC representative, the pair announced the big news at a party on Saturday to 50 of their family and close friends, Us Weeklyreported.
Ever since then, the mom-to-be has been documenting her pregnancy on Instagram with growing baby-bump photos and details regarding her cravings, morning sickness and moods -- or lack thereof.
It seems Tori's experience has been very enjoyable and easy thus far. Tori said she's had soft skin, feels graceful and happy, craves salty foods, and has suffered zero headaches.
Tori, who is of regular height, and her husband, who is a dwarf, anticipate their newborn will arrive in May 2017. He will be the first grandchild for Zach's parents, Matt Roloff and Amy Roloff, who also star on Little People, Big World. Zach's family runs Roloff Farm in Oregon.