When ET spoke to the Irwins in February, Terri said that her late husband would've been "over the moon" to become a grandpa.
"He would've been a good, good grandpa. Yeah, he really would've been," Bindi agreed. "I don't think we would've ever seen our daughter. He would've just whisked her away into the zoo and it would've been perfect."
In a tweet following Grace's arrival, Terri again shared how Steve would've felt about his growing family.
"Love is not a big enough word. My heart is so incredibly happy. And I know that Steve would be beyond proud," she wrote. "Grace is the next generation to continue his mission and message of conservation. She chose her parents wisely. Bindi and Chandler are already the best parents ever!"