A Broadway drama is in the making. It comes complete with a producer and playwright, sex and porno stories, accusations of lies and hidden assets – and the threat of juicy private inside theatrical information that dassn’t be tattled. The main characters, now facing off with divorce lawyers, are a wealthy, successful husband and his 25-years-younger second wife. The title is Smith vs. Smith.

Philip J. Smith is president of the Shubert Organization, which owns the largest number of Great White Way theaters. Dating back two centuries, it presented names like Lillian Russell, Sarah Bernhardt, shows like “The Ziegfeld Follies,” such 1940s biggies as Eddie Cantor and Fred Astaire. Its long ago headliners still resonate today – Fanny Brice, whom Barbra Streisand immortalized; Gypsy Rose Lee, whose “Gypsy” gets revived every other season. They brought us “Cats,” “A Chorus Line,” “Mama Mia!” The Shuberts are the most powerful force on Broadway.

Phil Smith is well-liked in his industry. By me, too. He has two adult daughters from a first marriage. He has health issues. This one is not a problem he needs. If he is or isn’t, its root cause will be for a court to decide – not me. Getting between a warring man and wife is not sane. If they get back together, the only one killed would be moi.

Enter now Tricia Walsh-Smith. British. Blond. Beautiful. Brainy. Bad background. All admitted: lousy first marriage, subsequent skid into a lifestyle best described as colorful. Broke, estranged from her child, an alcoholic whose younger brother Kevin’s alcoholism led him to suicide. Sober since ’94, and a known playwright whose first offering – “Bonkers” – was a hit in London, she’s written “Addictions,” a trilogy about the disease. Its proceeds go to The Program. Her newest play, “The Last Journey,” scheduled to open May 17 in the Westport Playhouse, suddenly didn’t. She leaves it to others to wonder if some powerful theatrical presence interfered.

Tricia is also my friend. She and Phil dated for years, married nine years. She’s seen him through physical difficulties. Maybe 10 days ago both sides reached out to me. Tricia came to my home Wednesday night. She’s saying:

No joint bank account, no joint credit cards. He earns approximately $1.5 million a year, and her allowance is $400 a week. She says: “Same as the maid . . . and when I spent $500 on shoes, he said, ‘You’re spending my daughters’ money.’ ” Upon his death, the marital nine-room Park Avenue apartment goes to them. She will be allowed to live in it one year. Her prenup (despite certain allegations and explanations) signed away community property rights. She’ll get their $350,000 Florida apartment plus his pension. She’s never seen the will. After he stated that, should he go to that great big stage in the sky, “my financial affairs are being managed by my daughters,” she requested a post-nup upgrade plus assurance his pension actually goes to her. This triggered the war.

Phil Smith understands I’m writing this column. He wanted to know, would I be hurtful to him? Absolutely no. Never. But this is not good for business. Who knows, it could result in yet another play. Phil, make peace.

THIS is my day for marital mis eries. We speak now of former L.A. Mayor Richard Riordan. After his wife, Nancy, requested a separation, he was inaccurately accused of having left her because he had two mistresses. Riordan, who now actually doubles as a professional comedian, called me to say: “Absolutely not true. My friends will tell you I’m too cheap to even have one.”

CNN’s Christiane Amanpour is giving up life in London. Mov ing back to New York with her baby and husband, Jamie Rubin, Madeleine Albright’s former press aide . . . The Hamptons did a charity geared to shoe fetishists. The Hilton sisters’ sequin sneakers went for $1,500, Dale Chihuly‘s glass pumps brought $2,600, Billy Joel‘s used tennis booties earned $3,000. Hillary‘s pair raised $4,000 . . . Trust mother, kiddies, re the ongoing Brooke Astor will hearings: It’s Not Going To Be Pleasant . . . As to Merv Griffin’s Crossword game show, let it be known the actual inventor of the crossword puzzle was himself buried 6 feet down and 3 across.

SO this hotshot Wall Streeter’s daughter is in labor. He sent word, “Tell her to hurry. The Labor Day holiday is coming up, and I don’t want to miss the week in Amagansett.”

Only in New York, kids, only in New York.