Supermarket worker dances while woman throws tantrum about wearing a mask

The woman who shot the video has been dubbed a "Karen" by online commentators. Photo / Twitter

Footage showing a supermarket worker breaking into a dance as a customer complains about having to wear a mask to enter the store has been spreading on social media.

The customer, who filmed the video herself, took offence to the rule that said she must wear a mask inside the store or else allow the store staff to shop for her.

Shelley Lewis, from California, has been dubbed a "Karen" by social media users, an internet term to define a middle-aged white woman acting entitled.

She believed it was a violation of her rights to make such demands.

The woman demanded to speak to the manager who explained her options to her. She grew increasingly upset as he calmly explained why she couldn't go in.

The woman tells the man that she has a "medical condition" that means she can't wear a mask.

"You're discriminating against me now, do you know that?" Lewis tells the manager as he offers to personally shop for her.

She then demands to get the phone number for the store's corporate office, threatening to complain.

Meanwhile, the staff member who first tried to explain the rule to her can be seen throwing some dance moves while disinfecting shopping trolleys.

Lewis tries to confront him about it and he simply tells her he is a happy man.

The video has been shared widely on social media and has had more than two million views in just a few hours, with people criticising the woman's attitude and applauding the store staff for the way they handled the situation.