Be careful where you stop for your morning coffee as you could come face-to-face with an unwelcome furry friend.

International coffee shop chain Caffé Nero has promised an investigation after a horrific video was published of rats running around one of its Irish branches. The coffee shop in question, located in central Belfast, remains shut today with a sign saying it is "closed for essential maintenance."

The footage in question was filmed almost a month ago by a couple walking through Belfast city centre after a night out. In the short video, a number of rats can be seen climbing across one of the coffee machines before the camera pans out to show the store's name.

It is often said that in a busy city you could be anywhere from three to 30 metres away from a rat at all times, and going by this video that distance could be a LOT shorter.

​Caffé Nero has its headquarters in England but has over 700 coffee houses worldwide in countries across Europe, the US and the UAE. As well as the Northern Irish branches, Caffé Nero also has four locations in Dublin.

Speaking to the Belfast Telegraph, the 24-year-old man who spotted the pests said he was stunned and felt he had to capture what he saw. "I couldn't believe it in such a well-known brand. I was quite shocked and stunned. That's why I started recording it, because I didn't think anyone would believe it," he explained.

"It was out of the corner of my eye I noticed one rat on the floor and then eventually another one, and I watched them climb up the counter top and in behind the coffee machine. Then I started recording it."

In a response today, a representative for Caffé Nero said an urgent investigation was underway. "This incident has only just been brought to our attention," the spokeswoman said. "We are taking it extremely seriously and will be conducting a thorough investigation as a matter of urgency."

Photo sources: Belfast Telegraph