One Manhattan woman thought she smelled a rat after getting a great deal on a dress — she didn’t know how right she was.

Cailey Fiesel, 24, of Midtown claims that an outfit she bought from the fashion retailer Zara had a dead rodent sewn into the seam — and she only discovered the disgusting situation when the dress started stinking and she felt the animal’s paw poking her in the leg, according to a new lawsuit.

“I saw the little leg that was coming out of the seam that I had touched, which was really horrifying.

“I froze — I was paralyzed with fear,” Fiesel told The Post at her lawyer’s office on Monday.

“I was in complete shock. My eyes saw that it was a mouse but my brain told myself it can’t be,” she said.

The Colgate University grad bought the black scoop-neck dress for $40 from a Zara location in Greenwich, Conn. in July.

At first, everything seemed fine. But when she finally wore the garment to work a few weeks later, she noticed a “disturbingly pungent odor” coming from it, she says.

“Despite getting up from her desk and walking around, she was unable to escape the odor,” says her Manhattan Supreme Court suit, filed Monday.

“I felt something brushing up against my leg and thought it was a string from the seam of the dress,” the 24-year-old said.

“When I went to pull at it, it didn’t feel like a string. I then felt the hem of the dress and it felt like there was some sort of sensor,” the talent agent recalled.

“I turned up the seam of the dress and saw it was not a sensor and that it was a mouse,” she said, stretching her fingers to show the approximately 2 ¹/₂ -inch length of the rotting rodent.

The shock changed to panic and Fiesel jumped out of her desk chair at her midtown Manhattan office and ran to the bathroom.

“I changed immediately. Thank god I had something to change into,” Fiesel said.

Her suit says she not only suffered emotional distress from the incident, but she also developed a large rash that was diagnosed as a “rodent-born disease.”

She’s suing for unspecified damages, saying the retailer owed her a “duty of care” to manufacture dresses that were “free from defects, including rodent infestations.”

“Zara is known for having quick turn around time,” explained Fiesel’s attorney, Adam Deutsch.

“They are known for taking a design that is popular and getting it on shelves very quickly, that is because they manufacture all their own material.

“The quickness in which they get things from design to shelf probably leads to their lack of controls.”

A label on the rodent-bearing dress says it was made in Turkey.

Deutsch has preserved the dress, with the embedded rodent, in a vacuum-sealed pouch to use as evidence at trial.

The lawyer said they tried to settle the claim outside court but Zara refused.

“She’s been a wreck ever since,” Deutsch said about his client.

“She should be compensated for what she went through,” he added.

A spokesman for Zara USA said the company “is aware of the suit and we are investigating the matter further.”

“Zara USA has stringent health and safety standards, and we are committed to ensuring that all of our products meet these rigorous requirements.”

There are rats are in our food, drinks, and even our clothes!