In a 2005 episode of “Entourage” a super-agent played by Malcolm McDowell tells Jeremy Piven’s Ari Gold that his eight-year-old daughter knew that Johnny Depp was going to be a star when she watched “Platoon.”

“You showed her ‘Platoon’ when she was eight years old?” the hyper-caffinated Gold asks incredulously.

The joke may be about bad parenting, but the reality is that Depp was marked for stardom by Hollywood almost from the time he first turned heads in the Vietnam drama. After a brief detour into teen heartthrob-dom with the TV show “21 Jump Street,” Depp began justifying that initial enthusiasm, amassing well received turns in the likes of “Ed Wood” and “Edward Scissorhands.”

The movie industry was so convinced that the actor possessed that rare alchemy of talent and charisma that marks a true star, that it stuck by Depp for over a decade until he found his box office footing. Finally, with 2003’s “Pirates of the Caribbean,” Depp made good on that faith, scoring a global blockbuster and earning an Oscar nomination to boot.

He quickly rose to the top of the A-list. His friendships with Hunter S. Thompson and Marlon Brando, fascination with pop culture flotsam and penchant for fedoras marked him as the most fascinating of the movie business’ biggest names. Stardom seemed a lark for him; a grand caper he couldn’t quite believe he pulled off.

Along with hits like “Alice in Wonderland” and “Charlie and the Chocolate Factory,” he offered glossy magazines good copy. He owned a country estate in France, an island in the Bahamas and dug Baudelaire — a trifecta guaranteed to leave Graydon Carter inflamed.

But with this failure of “Alice Through the Looking Glass” this weekend and a tabloid-ready divorce from Amber Heard dominating airwaves, moviegoers may be growing tired of the actor. As Deadline’s Anthony D’Alessandro notes, 35% of people cited Depp as the major reason for seeing “Through the Looking Glass.” Five years ago, 51% of moviegoers said the star was the reason they saw its predecessor,  “Alice in Wonderland.” It’s a signal that Depp’s reign, which lasted for much of the early aughts, could be nearing its end.

There have been flops aplenty. “Transcendence” and “Mortdecai” didn’t just bomb, they were excoriated by critics. “Lone Ranger,” a $225 million disaster that allowed Depp to fulfill a childhood fantasy of wearing a dead bird on his head, ranks alongside “Ishtar” and “Heaven’s Gate” as one of the film industry’s biggest disasters. And “Black Mass,” with Depp’s chameleonic turn as Whitey Bulger, reminded audiences of his shape-shifting talent, but cost too much and made too little. Plus, Depp’s lack of campaigning for awards contributed to a snub at Oscar time.

“Into the Woods” was a hit, but Depp’s work as the Wolf barely registered as a cameo, and wasn’t heavily emphasized in marketing materials. Aside from that it’s been a stream of duds and disappointments.

More damaging than the grosses, is that what made Depp so memorable and arresting — his rock star outfits, affected voice and scenery chewing performances — now feels tired. Depp still has the ability to break the internet. Witness the media furor over his legal headaches for sneaking his dogs into Australia. However, when it came to his bizarre, hostage-like video apology for violating the country’s laws, people were laughing at Depp and not with him.

His divorce from Heard could further erode his standing. The actress is claiming Depp physically abused her and was dependent on drugs and alcohol. Photos showing Heard’s bruised face have already appeared online.  In the case of “Alice Through the Looking Glass,” which was pitched at female audiences, the images may have depressed turnout.

Attorneys for the actor counter that the allegations have no merit and are an attempt to “secure a premature financial resolution.”  Yet, in the social media age, when stars’ personal lives and careers collapse on each other, scandals can do lasting damage to reputations. Stardom is always ephemeral. Many actors are lucky to spend a decade topping casting lists. Now, the immediacy of Twitter and Facebook is acting as a double-edged sword. It magnifies an actor’s virtues, propelling them into the popular consciousness, but if they stumble, the blowback is savage and unrelenting.

Like his idol, Brando, Depp could rebound. In the early ’70s, Brando was so out of favor that he had to submit to a screen test to win the part of Don Corleone. That led to an Oscar for “The Godfather” and another nomination for “Last Tango in Paris”; two films that cemented his legacy.

“Depp is a fantastic actor, thus will always have a draw with the right project,” said Jeff Bock, a box office analyst with Exhibitor Relations. “He needs to do what he always does…another pirate adventure and another team-up with his creative twin, Tim Burton.”

Looking ahead, Depp is following part of that advice to the letter. He will return for a fifth “Pirates of the Caribbean” and has signed on for a remake of “Invisible Man,” both of which could score commercially.

Depp will also have to prove that he still has what it takes to astound audiences — not because of his off-screen antics or bizarre costume choices, but with the intensity of his talent. That won’t be satisfied with another stint as Capt. Jack Sparrow. It may require facing the camera without the crutch of a gonzo hair style or an ocean of mascara.

“Audiences want to see the ‘Donnie Brasco’ Johnny Depp or the ‘Blow’ Johnny Depp,” said Paul Dergarabedian, senior media analyst at ComScore. “They want him to play a real character again.”

Correction: An earlier version of this article misidentified the actor playing the super agent in “Entourage.”