A fashion designer who launched Taylor Swift’s clothing line claims her Brooklyn business partner ruined her impending deal with Kylie and Kendall Jenner, according to a lawsuit.

“I got totally blindsided. I cried for weeks,” said designer Kate Liegey, who claims Mark Gadeh also shut her out of their clothing line without warning.

Liegey, whose line for singer Swift debuted in Hong Kong in 2016, says she was about to seal a deal to license a clothing line in China for the Jenners when Gadeh tried to steal the project while simultaneously ousting her from the clothing line she built for their partnership, The Front Row.Studio, according to a lawsuit she’s filed against him.

The firm earned praise from fashion insiders and a social media following, said Liegey, who not only designed the clothes but handled photo shoots and directed the building of the website for the clothing line.

“I put my heart and soul in it. I worked 18-hour days,” she told The Post. “I was a one-woman show.”

Gadeh, an apparel company exec, reached out to Liegey by cold-calling her after he saw articles about her work with Swift, she said.

“He called me and started pursuing me. ‘You’re an unbelievable designer, we should do business together,’ so I hung up on him,” she recalled.

But Gadeh persisted, eventually flying to California to meet with Liegey, who said she checked out his credentials before agreeing to partner with him in 2016.

She’d long dreamed of starting her own clothing line, calling the venture “a great opportunity.”

Gadeh promised to pay Liegey $8,000 a month, to eventually make her a principal of their company, and to share profits with her, but he “never intended to carry through on the promises he made,” she now charges in court papers.

He rented a Chelsea condo as a showroom for their work that doubled as Liegey’s apartment.

But after he convinced her to move to New York, Gadeh allegedly stopped paying the bills and kicked her out in April 2017.

“I never argued with him. There was no bad blood until just this bizarre end of the relationship. He just said, ‘Get out,’” she recalled. “I was homeless on the street, I didn’t know what to do. I just could not understand why the man would do this to me.”

He even wiped out her final $8,000 payment, made via PayPal, by claiming to the app that Liegey wasn’t entitled to the dough, she claims.

Gadeh didn’t respond to a message.