No wonder Katharine Hepburn asked biographer A. Scott Berg to wait until she died to publish ''Kate Remembered.'' In the book, which hits stores on Friday, Berg recounts 20 years of conversations with the screen legend, in which she offered some startling revelations. Among them: that once, during her three-decade affair with Spencer Tracy, the drunken actor struck her. ''While Kate was trying to put Tracy to bed, he smacked the back of his hand across her face. She said he was so drunk she believed he neither knew that he'd done it nor that he'd remember.'' She never reminded him of the incident or let it drive her away. ''I loved him. And I wanted to be with him. If I had left, we both would have been miserable,'' she said.
Of course, throughout their affair, Tracy remained married to wife Louise. Shortly after he died in 1967, Berg writes, Hepburn phoned his widow. ''She said: 'You know, Louise, you and I can be friends. You knew Spencer at the beginning, I knew him at the end. Or, we can just go on pretending.' 'Oh, yes,' Louise said, 'But you see, I thought you were only a rumor.' Kate never got over this story. 'A rumor!' she said to me. 'Can you imagine? Thirty years her husband isn't there, and she thinks I'm a rumor.'''
Other revelations: Hepburn posed for nude photos once during college and always feared they would emerge. She once invited Michael Jackson to dinner, where he claimed she was his favorite movie star but seemed unable to name any of her films, then dined on what he called ''white broccoli,'' apparently never having seen cauliflower before. As soon as he left, she called her housekeeper ''to get the whiskey.''
As for other current celebrities, the book says she liked John Travolta in ''Saturday Night Fever'' and was a fan of Harrison Ford. On the other hand, she had ''zero tolerance'' for Woody Allen, didn't understand Arnold Schwarzenegger (his accent, that is), and found Meryl Streep (who finally surpassed Hepburn's record of 12 Oscar nominations this year) to be ''her least favorite actress on the modern screen.''