A New Jersey man let a new-to-the-city pal stay in the Manhattan apartment he keeps on the side — but when he asked her to leave, he discovered she was renting it out on Airbnb, according to a new lawsuit.

Brianna Hallam started staying at Alec Jain’s $3,800-a-month rental in September 2016 “while she looked for an apartment of her own,” his Manhattan Supreme Court suit says.

When he asked her to leave a month later, she refused, the suit says.

Then Jain, 30, found out that Hallam, 25, was renting the unit out on Airbnb — and had moved all of his personal items including jewelry, electronics and clothing out of the apartment, according to court papers.

He contacted the website and they removed the posting, but Hallam created new accounts and continued listing the apartment, the suit says.

When Jain tried to evict Hallam again she filed a Housing Court action against him, claiming an illegal lockout.

Hallam’s attorney, Richard Rosenblatt, said his client won the Housing Court action after claiming that Jain improperly removed all her belongings, leaving behind just a flower and a pair of soiled underwear on the bed.

Rosenblatta said “there’s no Airbnb going on whatsoever.”

Meanwhile Jain’s facing $18,0000 in fines from his landlord over the Airbnb sublets. His attorney did not respond to requests for comment.