(INSIDE EDITION) -- Wait a minute, the parents cried. Back that video up!
Makelle Ahlin, who is 22 weeks pregnant, was undergoing an ultrasound as her husband, Jared, looked on.
As the fetus came into focus, the parents gasped. "My husband was like, 'Stop! Go Back! Let me see that!'" Makelle said.
And there it was, a tiny little hand raised in the ‘let’s rock!’ salute, complete with extended index and pinky fingers.
"I was in shock," Makelle told InsideEdition.com. “I said, 'Are you kidding me?' I’ve gotten ultrasounds with my other two babies and they were never doing anything."
The couple was highly amused, and that made the technician’s job more difficult, Makelle said.
"We were just laughing so hard," she said. "I guess it’s kind of hard to take video when someone is laughing and shaking."
The 27-year-old has two boys, ages 4 and 2. She showed the sonogram photo to the eldest, who laughed, too. "Then he wanted to see photos of himself," his mother said. "He’s at the age where it’s pretty much just all about him," she said, laughing.
Makelle and Jared know the sex of their third child, but they haven’t told their extended family members. The parents plan to make the announcement Friday with a reveal video.
Since she posted the ultrasound image to Facebook, Makelle has been getting calls from network news reporters.
"It’s amazing," she said.
Initially, she said, she had posted the sonogram picture to her Instagram account. "No one believed me and everybody thought it was a joke," she said.
But on Facebook, most everyone had the same reaction as the parents, who proudly note that their third child "is jamming and rocking" in utero.