The multimillion-dollar lawsuit Whitney Houston's father lodged against her has given him so much stress, he's been admitted to a hospital, his business partner said yesterday.

"He was sick before the lawsuit, but it definitely amplified his condition," Kevin Skinner told the TV news magazine Inside Edition.

John Houston, 81 -- whose company filed a $100 million breach of contract suit against Whitney in September -- was admitted on Nov. 20 to Columbia-Presbyterian, where he underwent treatment for stress-related disorders, Skinner said.

The suit alleges that John Houston's Newark-based promotions company turned around the diva's career by getting marijuana charges dropped in Hawaii and negotiating her $100 million contract with Arista Records -- but was never compensated.

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