A cat in China has become an Internet sensation after it underwent what seemed like a double eyelid surgery, emerging with bigger eyes.

Photos of Feifei - meaning Fatty in Chinese - posted on the Chinese social media platform Weibo, showed the feline in Chengdu before and after the surgery.

Before the surgery, its eyes were droopy and half-closed, making it look lazy and grumpy.

After the surgery, it was seen with stitches underneath its eyes. Another photo showed Feifei with fully opened eyes.

The photos have been liked about 35,000 times since they were posted in the middle of this month.

According to the Weibo user who posted the photos, the cat had to undergo the procedure as its eyelids were folded inwards.

Veterinarian He Jinyi, who operated on Feifei last month, said the procedure was not a cosmestic one but a necessity. Feifei's condition could have caused irritation or infection if uncorrected, as its eyelashes were rubbing against its cornea, reported the Chengdu Business Daily.

Feifei had been brought in by two animal welfare group volunteers who found it in March and noticed something wrong with its eyes, according to one of them, known only as Chen.

Dr He shared that the problem was only discovered when Feifei was brought to the clinic, and the surgery, which cost almost 2,000 yuan (S$403), took about half an hour.

Chen added that Feifei is now living with a local family.

"The photos are a hit online because the changes in the cat's eyes are so dramatic," Dr He told Chengdu Business Daily.