Go ahead and give him an Oscar already. 

After all, Johnny Depp’s best performance is also probably his last. 

Taking the stand Tuesday, Depp’s hourslong testimony, delivered in a soft, often halting voice, sounded nothing like a strident defense against spousal abuse. 

Instead, Depp depicted himself — brilliantly — as a confused, sad, gentle soul who somehow stumbled into global fame and ungodly wealth. 

As if the .000000001% of people who attain worldwide recognition and fortunes of more than $600 million get there by accident. 

At one point, Depp even stood up in the witness box to reenact his mother’s suicide attempt. 

Can you imagine? Selling out a parent’s lowest moment for public sympathy? 

This isn’t just the diminution of Johnny Depp. We’re watching the Death of the Movie Star. 

What COVID has accelerated — the shift to streaming platforms, all but Marvel movies playing at multiplexes, the waning influence of the celebrity-industrial complex — Depp and his peers are actively destroying. 

Will Smith demolished decades of public goodwill with The Slap. 

Alec Baldwin and his utter lack of remorse. 

Brangelina, the last great, grand Hollywood romance. 

Julia Roberts! Once the epitome of an established Hollywood A-lister, she is now making the rounds shilling her new show on Starz — not HBO, not Showtime or Netflix or Hulu — Starz. 

And no one cares. 

Ever-shrinking stars 

You could argue that this is the inevitable result of our confessional culture — just about anything is forgivable if, in reality-TV parlance, you Own It — and technology, which has collapsed our biggest stars into Instagram thumbnails, avatars we access and dispose of at will. 

I thought about this a few days ago, after hearing that the late Paul Newman’s autobiography will be published this fall. 

Follow the Post’s live coverage of the Johnny Depp-Amber Heard defamation trial

The chance that his memoir contains a whiff of scandal is nil — his grown children have control of the release. 

But the book is of automatic interest precisely because it’s a relic, a reminder of a time when illusion mattered. 

Post-Harvey Weinstein, it’s impossible to believe. Or, really, to care. 

We can probably count on one hand how many genuine movie stars are left: Brad Pitt. Leonardo DiCaprio. Sandra Bullock. But their status relies as much on mythmaking — none are active on social media — as professional prestige. 

And Pitt, unlike Depp, was smart enough to litigate his divorce behind closed doors. 

Sob-story soliloquy 

In pursuit of this Pyrrhic victory, Depp sat on the witness stand and offered up all his childhood trauma: emotional and physical abuse at the hands of his parents; taking his mother’s “nerve pills” at age 11; his mother’s impoverished background, raised in the shacks and hollers of Kentucky; and a jump-cut to his addiction to the opiate Roxicodone, doing cocaine with Heard’s sister, Whitney, the “pure horror of detoxing.” 

He also testified to the details of his affair with Heard — details their former partners probably did not know until now. 

For nearly four hours, Depp droned on and on. Really, who can blame him? God knows when he’ll next have such a captive audience. He’s totally unemployable. 

Little wonder much of his testimony sounded like an extended, masturbatory “Inside the Actor’s Studio” episode, Depp talking in great detail about his early career, where he studied acting, how he created Edward Scisssorhands and Captain Jack Sparrow, his diet and exercise regimen for “Donnie Brasco,” his favorite writers and musicians and his love of old blues . . . it never seemed to end. 

He quoted himself in an interview he gave to TV Guide in 1989! 

This is ostensibly a defamation trial, yet we heard Depp give such testimony as: “ ‘Fear and Loathing in Las Vegas,’ which I was lucky enough to make into a film with Terry Gilliam . . .” 

The charm offensive 

The narcissism was mind-numbing. But the performance — wow. 

With his knitted eyebrows, shy smiles directed to his ex-wife, his apologies over proper gender terminology, a thoughtful “bless you” to a sneezer in the courtroom — it was easy to forget that this was a spoiled actor who blew up his Disney franchise over drug use, who squandered his $650 million fortune, who asked his private female nurse for drugs he described as “some f–king knock-out yum-yum” and for “some morphine to see if my tongue and penis touch,” who described Heard in texts as “this waste of a c-m-guzzler” and a “dangling, overused flappy fish market” who he would like to set on fire and then “f–k her corpse” . . . et cetera. 

And like the best actors on press junkets, Depp treated every question asked by his lawyer — questions he surely heard over and over in hours of courtroom prep — as if he was hearing them for the very first time. His answers sounded totally off-the-cuff. At times, the questions seemed to take him by surprise. 

He does vulnerability well. In fact, Depp was so charming I found myself wanting to believe him — even as I knew, really, this was just another act by a dark star, imploding.