Happy and this baby knows it! Watch incredible ultrasound of fetus clapping

/ Source: TODAY

Proving you're never too young to be an Internet star, an ultrasound video that shows an unborn baby clapping to a children's song has gone viral.

Mom Jen Cardinal posted the clip on YouTube Thursday, writing, "At our 14 week ultrasound our baby was clapping, so I sang a song with our doctor as my husband filmed."

The video shows the fetus clapping seven times as Cardinal and her physician can be heard off-camera singing, "If You're Happy and You Know It."

Some commenters were quick to call the video fake, but Cardinal told TODAY that while her doctor manipulated the footage to extend the applause, the first three claps were indeed "very real."

“We went for an ultrasound. Our baby clapped two or three times. We gasped, laughed," she said. "Doctor said, 'let's sing a song.' He rewound and replayed it to us singing, so it looks like the baby is clapping. Great fun.”

A spokesperson for the American College of Obstetricians and Gynecologists told TODAY.com that it's plausible the baby did clap at least once, explaining, "Fetuses make all sorts of meaningless movements in utero without knowing that they are doing it — but if the clapping movement is real, it only happened once and they probably edited it to repeat."

Watch the video above to see the musical moment for yourself — and if you missed it, check out this ultrasound image that shows a tyke flashing a thumbs-up sign, dubbed the “Fonzie fetus,” after Henry Winkler's character on “Happy Days."