A stunned couple has discovered a hidden room in their new flat just days after they moved in.

The secret space, which was found by the two renters at the back of a cupboard in the corner of their kitchen, even has a window.

There is, however, no door to access the room normally. It has no flooring, and still appears to have some wiring and building materials left inside.

According to Yahoo News Australia, an unnamed woman from the UK posted the incredible find on a Facebook group called ‘Things Found In Walls – And Other Hidden Findings’.

Sharing her surprise, she wrote:

“Just rented a flat with my boyfriend and found a room inside our kitchen cupboard.”

“Definitely gonna leave something weird in it for the next tenants when we move out..”

Other than the surprise entrance in the kitchen, there is no way to enter the secret room

Fellow members of the group commented in astonishment and offered some theories on what the room might be for.

One mum posted: “I would turn it into a hide out to study or hide and eat my kids’ fave snacks so I wouldn’t have to share with my kids”

Another aggrieved mother wrote: “I would totally make that into a comfy little hiding spot. Is husband getting on your nerves? Run to the hiding spot.”

One commenter suggested: “I would totally make that into a comfy little hiding spot”

Others were more outlandish with their guesses. One speculated it could be the potential work of a serial killer:, saying “Perfect place to hide the bodies”

Alternatively, some took a scathing look on those who built the property, calling it a “waste of good, natural light”.