As recent events prove, the truth is harder than ever to come by in showbiz.

IN HOLLYWOOD, lying is often treated like a big joke. Oft-quoted producer Lynda Obst famously titled her showbiz memoir “Hello, He Lied,” and now entire reality shows — “Joe Schmo,” “Joe Millionaire,” heck, about anything with “Joe” or “Obnoxious” in the title — are built around obfuscation.

Lately, though, the whoppers have been served up faster than lunch hour at Burger King, highlighted by two personnel changes that bookended the Memorial Day weekend.

Leading the pack were the folks at Comcast and E!, who not only insisted for weeks that network prexy Mindy Herman wasn’t going anywhere but were positively indignant that anyone would suggest otherwise — right until they announced her departure.

In similar fashion, Viacom president Mel Karmazin stated as recently as five weeks ago that he had no plans to leave the company — after endless gossip about his fractious relationship with chairman Sumner Redstone — before the rumor finally became reality Tuesday.

This casual relationship with truth — down to the Clinton-esque parsing of words like “is” — might sound like no big deal, especially when it comes to fending off pesky reporters. Yet I’d argue there is a potential price to be paid.

FOR STARTERS, the rest of the TV industry can thank the folks at E! and Comcast for the heightened skepticism with which they’ll be greeted the next time someone denies a rumor. Fool me once, shame on you. Fool me twice, shame on me.

More significantly, this comes when trust in the media and particularly the press has been rightfully shaken. Part of that stems from transgressions by reporters — the New York Times’ Jayson Blair, the New Republic’s Stephen Glass, USA Today’s Jack Kelly — but there’s also the Times’ public mea culpa last week regarding its reporting on Weapons of Mass Destruction.

While journalism has taken a deserved beating for its sins, reporters invariably depend in part on sources telling the truth — especially those in positions of power who have something to lose if they’re caught lying, since said scribes will theoretically have to deal with them again. (Remarkably, the reporter most culpable in the Times’ WMD coverage, Judith Miller, has essentially crawled into bed and pulled the covers over her head. No offense, but if my editors ran a similar note implying that I messed up, I’d either defend myself or admit to the screw-ups.)

Still, forget the annoying press. What about other constituencies that Hollywood must woo? A reputation for lying doesn’t help the next time Congress gets its panties in a bunch, wanting TV to clean up its act. Indeed, there’s already a sense that moguls will say whatever it takes to escape the hearing room unscathed, then quickly return to business as usual.

THE SAME PROBLEM applies to networks pitching advertisers, who have finally begun wising up to the fact that those elaborate upfront sales presentations touting the fall season are frequently a shell game — an elaborate case of bait and switch. Actually, it says something about the collective intelligence along Madison Avenue that they’ve fallen for the same Jedi mind tricks this long.

Call me naive, but I’d like to think that when truth becomes this elastic, it’s inevitably going to snap back at you. At minimum E!, which is ostensibly a news organization (laugh, titter, guffaw), should worry about its credibility (titter, guffaw, laugh) and how contacts deport themselves when the shoe is on the foot.

Early in my reporting career, I remember asking a source about a rather unpleasant rumor that was making the rounds. “See, I’m never sure when I should lie to you,” he said, to which I responded: “That’s easy: Never — at least, if you want me to believe you ever again.”

That’s a lesson that especially applies to corporate spokespeople, who will exhaust plenty of employers in their careers if they’re lucky enough but will likely face the same curmudgeonly reporters and critics until someone decides to impose term limits on us. Rest assured, if your denial might as well be a river in Egypt, you’re not going to be terribly useful to any future boss, much less the one that just got fired.

All this brings to mind a favorite scene in “Excalibur,” where Merlin tells nasty King Uther why the world has caved in around him. “You betrayed the Duke, stole his wife and took his castle,” the wizard hisses. “Now no one trusts you.”

A few centuries have passed, but not much has changed. Just ask the folks at E! and Comcast.

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