Footage of a baby crying whenever her mother sings a particular song that she made up.

The video, filmed in New Jersey, USA on April 18, shows little Harmony Grace getting emotional as her mother sings.

Her father later wrote online: "My wife told me our baby girl Harmony Grace always cries when she sings her this song she made up.

"So I turned on the camera and sure enough Harmony Grace cries only when she sings her this song."