The former couple's son Zach, 26, and his wife Tori welcomed their first child, a son named Jackson Kyle Roloff, on May 12.
The big boy weighed a whopping 9 pounds, 1 ounce, and measured 20.5 inches long.
The proud new dad announced the news on Instagram last night.
"Love him," he gushed.
New grandma Amy, 52, was overwhelmed with joy.
"I'm so proud, so happy I can't contain myself!" she wrote on Instagram. "I love them! My grandson is perfectly perfect!"
Finally in agreement on something, Amy's ex-husband Matt, 55, echoed the excitement.
"I'm a grandpa!!!" he said on Facebook.
As RadarOnline.com readers know, Matt and Amy have been at odds since the family patriarch went public with his assistant and farm manager turned girlfriend, Caryn Chandler, 49. (Amy and Caryn have known each other for years, and were once friends.)
"Now that they're dating, of course that's hurtful," Amy recently admitted on camera.
Matt and Amy separated after nearly 30 years of marriage in 2014. The split was finalized in May 2016.
We pay for juicy info! Do you have a story for RadarOnline.com? Email us at email@example.com, or call us at (866) ON-RADAR (667-2327) any time, day or night.