It was the best lease ever — until the lawsuit.

An Upper West Side man who decided to stop shelling out for his West 93rd Street pad allegedly forced his landlord to sign a contract letting him stay in the apartment for free as long as he wanted.

Apartment owner John Fiore says tenant Steven Harrison presented him with a new lease that specified Harrison “would not pay [the] Landlord any rent directly,” and could renew any time he wanted.

When Fiore had the lease revised by an attorney, he claims Harrison ripped up the altered lease and held hostage Fiore’s laptop with all of his musical arrangements and financial information.

Fiore signed on the dotted line, according to a Manhattan Supreme Court lawsuit he filed. The lease expired last week, and Fiore is seeking back rent. Harrison said the allegations were “distorted.”