Here's a viral video that deserves a round of applause.

YouTube user Jen Cardinal posted an incredible ultrasound video Thursday of her 14-week-old unborn baby "clapping along" as she and her physician sing "If You're Happy and You Know It," as her husband films.

She explained in the comments under the video, "The experience is one I'll never forget, the baby clapped three times, then the doctor rewound and scrubbed it while we sang. No mystery. It was amazing."

Watch the amazing ultrasound video below.

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