A concerning video of pop star Katy Perry appearing to suffer a worrying eye issue while performing in a recent concert in Las Vegas has sent fans into a frenzy.

The 38-year-old singer was performing at her Vegas residency on Sunday (local time) when something apparently went wrong with one of her eyes.

In the clip, Perry can be seen posing and staring into the audience before her right eyelid repeatedly closes apparently uncontrollably.

Footage of the incident has since gone viral, with the video receiving more than 19 million views since it was published.

The Roar singer can be seen multiple times in the short clip using her hand to try to lift her eyelid back to normal, only for it to close again. She was also seen pressing on her forehead to try to open her eye.

With all apparently back to normal, Perry continued on with her show without addressing the weird moment.

The video sparked concern and speculation from fans, with a rush of comments joking that Perry was a robot and had suffered a “glitch” or mechanical failure.

“She’s glitching,” one user commented on TikTok.

“That baby doll you had as a kid with the eye that kept closing,” said another.

Meanwhile, other social media users suggested the issue was due to a misleading anti-vaccine narrative about side effects from COVID-19 vaccination.

Perry has been an outspoken supporter of COVID vaccines. Memorably, she dressed up as the coronavirus vaccine last Halloween with Orlando Bloom, writing in the caption on her social media that “I vaxxed a girl and I liked it”.

Fans who responded seriously to the singer’s viral clip claimed it was because of Perry’s “eyelash glue getting stuck to her bottom lid”.

Perry has yet to publicly comment on the viral video.