Johnny Depp is such a consistently surprising actor that when he jumped out of a chocolate box as Willy Wonka in Tim Burton’s latest film he seemed to add another layer to the mystique that envelops him. Yet the Hollywood star can be read like an open book if you know where to look.

A proliferation of body tattoos chart his journey through life, proclaiming his rites of passage like labels on a well-worn suitcase. There are insignia for Betty Sue, his beloved mother, his children Lily Rose and Jack, an Indian chief and many others including the actress Winona Ryder, whose accolade “Winona Forever” was surgically shortened to “Wino Forever” when their engagement came to a messy end.

For the 42-year-old heartthrob’s legion of fans, at a subliminal level there are beguiling parallels between Depp and Wonka — a much darker character than Gene Wilder’s depiction in the 1971 version of Roald Dahl’s story Charlie and the Chocolate Factory. Both are reclusive prodigies inhabiting secret worlds. Depp’s magical retreat is a village near St Tropez in the south of France, where he lives with his beautiful girlfriend, the French actress-singer Vanessa Paradis, and their children.

His Wonka (whose porcelain pallor, pageboy bob of hair and lavender gloves make him a dead ringer for Michael Jackson) is also something of a show-off. A psychologist might venture that Depp himself is a reverse exhibitionist, whose withdrawal from Tinseltown and denunciations of its tacky values draw attention to his artistic purity as — paradoxically — one of its A-list stars.

Then there’s Wonka’s sadism in the glee he derives from the mishaps of his young visitors. Depp a sadist — surely not? Maturity has lent him a wholesome patina, but callousness was the tenor of headlines when he dumped the British model Kate Moss in 1998. His crocodile tears (“I cried for a week when we split up”) were contrasted with the discovery soon after that he had taken up with Paradis, who was four months pregnant.

Depp’s very appearance proclaims his otherworldliness. A slight, dark-haired man of part-Cherokee descent, he has a boyish man’s face dominated by molten brown eyes and scalpel-sharp cheekbones, often concealed behind an artist’s beard and dark shades. He projects an androgenous look that prompted one writer to remark that he’d be a woman if he were any prettier, although this overlooks his deep, husky voice and the string of girlfriends he has dated.

The package is completed by an air of weirdness that evokes Edward Scissorhands, his early study of melancholic fragility that signposted his path as a versatile and courageous actor. He has a collection of dead insects preserved in Perspex and was in the habit of giving live bugs as gifts. He returned from a trip to Peru with 24 lacquered, stuffed piranhas and a bat. He used to live in a Hollywood mansion once owned by the horror movie star Bela Lugosi and his best friends include the Gallagher brothers of Oasis.

With the weirdness went the wildness. In 1999 he chased a group of photographers with a plank of wood when he spotted them waiting for him outside a restaurant. He was subsequently arrested and spent six hours in jail. “It was the right thing to do,” he maintained, holding out the same treatment for snappers skulking around his French home.

He trashed a hotel room during a phase when he was “self-medicating” in a rebellion against his fame. “My drug of choice was alcohol — hard liquor, spirits,” he recalled. “Back in those days I literally had to be drunk to be able to speak and get through it. Success or notoriety or fame, I knew it wasn’t what I wanted.”

Depp met his match when he spent three months with the late Hunter S Thompson to research his memorable depiction of the gonzo journalist in Fear and Loathing in Las Vegas. At Thompson’s fortified compound in Aspen, Colorado, Depp expressed an interest in a nickel-plated shotgun hanging on the wall.

“He took it down and said, ‘Come with me’. Then he hands me this thing the size of a matchbox. I ask what it is and he says, matter-of-factly, ‘Oh, that’s nitroglycerine’. The next minute we were out in the garden firing shots at this home-made bomb. I hit it first time.” The explosion was spectacular.

Depp’s career was slower to ignite. His avoidance of mainstream films (he turned down the Brad Pitt part in Thelma & Louise) made him regarded as box office poison until two years ago, when the money men took note of his outrageously funny turn as Captain Sparrow in Pirates of the Caribbean, a performance inspired by the Rolling Stones guitarist Keith Richards. The movie was an unexpected smash hit, generating $200m in four weeks. He won his first Oscar nomination, an accolade repeated last year for his portrayal of J M Barrie in Finding Neverland.

Until Depp came into the world, the Kentucky town of Owensboro rejoiced in its sobriquet as “barbecue capital of the world”. On June 9, 1963, it became the birthplace of John Christopher Depp, the youngest of four children. His father, John, was an engineer and his mother a waitress.