An amusing video has emerged of a 6-month-old baby crying as she sees her mother with a face mask on.

The footage, shot on July 25 in Plymouth, PA, USA, shows Carter first smiling as she looks at her father before she bursts into tears when seeing her mother.

"Carter has never seen anyone with any sort of mask on their face so I was curious to see how she would respond," the father wrote online.

"When she heard my voice she smiled and looked at me but then you can see her facial expression turn into pure terror," he added.

While my fiancé was giving our 6 month old daughter a bath I was trying out my new face mask from Lush. Carter has never seen anyone with any sort of mask on their face so I was curious to see how she would respond. When she heard my voice she smiled and looked at me but then you can see her facial expression turn into pure terror! It was hysterical!