A UK woman has been left “speechless” after uncovering a mysterious feature in her backyard.

Nelly, who is originally from Bulgaria, purchased a timeworn terrace in a small Welsh town last year for £75,000 ($151,000).

She had first spotted the old optometrist’s shop in Treharris five years ago, and dreamed of one day turning it into a café and bakery.

“When it finally went on the market, I took a chance – and got it!” she explained in a TikTok caption. 

Nelly bought the old shop in 2024. Photo: T. Samuel Estate Agents

Behind the shop was an overgrown backyard completely swallowed by a jungle of weeds and brambles.

“I honestly don’t know what I’ll find down there,” Nelly said.

As she slowly cleared the foliage away, she spotted a mysterious white door hidden behind a curtain of ivy.

“My mum in law was very curious and wanted to help me clear the area faster and find out what is hidden behind the door,” she explained in a now-viral video. 

Nelly is documenting her renovation on TikTok. Photo: TikTok/@thebakeryproject

At first, Nelly assumed it was an outside toilet.

But when they pulled the wooden door aside and peered inside, they discovered a secret room filled with ladders, old furniture, and even a stone fireplace.

“I bet the sellers would have asked for more money if they knew this room existed,” Nelly said, adding there had been no mention of an extra room in the property survey.

The door led to a hidden storage room. Photo: TikTok/@thebakeryproject

She speculates it may have once been used as an extra kitchen for cooking.

Others in the comments suggested it might have been a laundry or scullery.

Nelly said the extra room came as a pleasant surprise.

“My gut was telling me something disgusting was behind the door, hence the shock and excitement,” she said.

Her plan is to use the garden room as an office once her bakery business is up and running.