“There’s no business like show business” was a great lyric in its time, but today it might be revised to “There’s no business like the celebrity business.”

Movie stars today regard themselves as “brands” and seem more interested in endorsements than acting credits. The celebrity craze has spread not only to the faux stars of reality shows but also to doctors, attorneys and other professionals, sometimes compromising their credibility.

Magazine editors were grateful last week for an excuse to run photos of Katie Holmes and Tom Cruise because every cover lately has featured Dr. Mehmet Oz. Discovered by Oprah, the cardiothoracic surgeon has been emblazoned on the covers of Time, Good Housekeeping, Shape and Prevention, with editors reporting increased newsstand sales.

“Oz understands the promotion world as he understands your lower intestine,” Richard Stengel, managing editor of Time magazine told the New York Times. The 52-year old Oz was not above dancing to “I’m Sexy and I Know It” on television, and TMZ runs photos of him shirtless on the beach.

Inevitably, his ubiquity has spawned “I hate Dr. Oz” web sites and Facebook pages created by husbands who are paranoid about the Oz mystique.

Another celebrity doctor, Dr. Drew Pinsky, ran into trouble recently when it was revealed that he praised a drug while accepting payment from its manufacturer. Dr. Drew, who seems to be everywhere on TV, recommended an antidepressant called Wellbutrin on the grounds that, unlike similar drugs, it did not suppress sexual arousal and, in some cases, actually enhanced it.

What he didn’t say was that he had accepted two payments from GlaxoSmithKline totaling $275,000 for “services for Wellbutrin.” The payments were revealed in a complaint filed by the U.S. government in federal court, which resulted in a $3 billion settlement.

Many stars reveal a conflicted attitude toward celebritydom. Alec Baldwin has flirted with the idea of running for public office and seems ubiquitous on the New York celebrity circuit, yet he made the columns last week for trying to punch a news photographer and became a hero of the tabloids by leaving phone messages for his daughter. A calmer persona emerges on Baldwin’s Capitol One Venture Card commercials. It seems appropriate that Baldwin played an important role in the latest Woody Allen film, “To Rome With Love.” One theme of the film is the mixed impact of fame — the life of an obscure citizen in Rome unravels when he becomes an instant celebrity.

Woody himself, to be sure, has benefited from his fame by exercising total control over every aspect of his filmmaking. Yet few public figures seem more uncomfortable in any public setting than Woody, who fidgets, snaps and simply turns his back when confronted by admirers he does not recognize.

Overall, the celebrity bandwagon is a seductive one in terms of lifestyle and payoffs, but dangers lurk at every turn. Plenty of billionaires are prepared to write a big check to ensure the appearance of a top performer at their birthday party or their son’s bar mitzvah, but Usher, Mariah Carey and Beyonce were embarrassed when Wikileaks revealed that Muammar Gaddafi had paid them $1 million in 2011 for a “special appearance.”

Since Beyonce averages about $80 million a year (according to Forbes), she didn’t seem to need another payday from a notorious dictator. She ultimately gave back the money.

The Zanuck touch

Growing up amid dynastic intrigues and power struggles, Richard Zanuck had every right to be a terrible person. Yet he always impressed me with his patience and thoughtfulness.

His father was the prototypically bombastic studio czar who had extraordinary impact on Hollywood’s golden era. Richard, too, displayed great talent when he assumed control of the Fox studio, but he made his greatest impression on his contemporaries when he shifted to the role of independent producer. He no longer controlled the “greenlight” but he worked his way through the system, taking meetings with executives half his age and listening to their notes. The list of films he fostered is extraordinary in range and quality, from “Jaws” to “Driving Miss Daisy” to “Alice in Wonderland.”

As a young studio executive, I once went up against him trying to wrest the rights to a screenplay titled “Butch Cassidy and the Sundance Kid.” Acting with his usual decisiveness, Zanuck swept it off the market. Encountering him at an event that night, Richard came over, gave me a pat on the shoulder and smiled. “Gotcha,” he said, with a good-natured bit of one-upsmanship. I understood that when he wanted something, he was usually right and there was no way of beating him.