Michael Jackson wanted to buy them, but the Elephant Man’s bones remain where God left them – at London Hospital.

“They didn’t think it was apt to let them out of the hospital,” said director Sean Mathias, wryly.

Mathias, who directed Broadway’s revival of “The Elephant Man,” opening tonight at the Royale Theater, believes Jackson’s loss is the theater world’s gain.

To research his take on Bernard Pomerance’s Tony-winning, 1977 play – based on the life of the grievously deformed but sweet-souled John Merrick, who died in 1890 – Mathias visited the hospital on Whitechapel Road.

There he saw the basement apartment (complete with a little fireplace) where Merrick lived out his final years, safe from taunts and beatings; the balsa-wood model of St. Phillip’s Church he painstakingly constructed with his one usable hand; and the cap and mask he wore whenever he ventured onto the hospital grounds.

“His head was so huge that the circumference of that cap was enormous,” Mathias marveled the other day, his own head looking rather small above a chunky silver choker.

“The mask was made out of cloth and had a cutout for his good eye. He wore it because he didn’t want to frighten other people. He used to walk around late at night in his mask and cloak – he must have been quite a figure.”

So is Billy Crudup, who stars in the play. Unlike David Lynch’s 1980 film of “The Elephant Man,” in which John Hurt was unrecognizable under a mass of makeup, the play puts the onus on the audience to imagine Merrick’s deformities.

And so, like David Bowie and others who’ve played the part before him, Crudup must contort himself in ways that suggest Mer- rick’s heavy head, twisted mouth and mangled body – for one hour and 40 minutes, without intermission.

“Billy is brilliant,” Mathias said. “He’s extremely imaginative and courageous for such a young actor, and very much in control of his ego.”

Mathias, 46, was once a young actor himself. Growing up in Wales, he was still a teenager when he performed in regional productions, including “Hair,” during which his mother caused a commotion in the balcony.

“Oh my God!” he remembered her screaming during the nude scene. “You can see his d- – -k dock!”

Shaken but undeterred, Mathias continued to perform, appearing several years later with a Welsh troupe at the Edinburgh Fringe Festival. It was there he met Ian McKellen.

They were together for the next nine years.

“It’s difficult to live with such a powerful person,” Mathias said. “He was 17 years older and famous. It was frustrating – and it’s partly why I turned to writing.”

He wrote a novel and several plays, one of which – “A Prayer for Wings,” about a disabled woman living with her prostitute daughter – he ended up directing.

That was 15 years ago, and Mathias (who lives in South Africa these days with a younger man, the writer Myer Taub) has been directing ever since.

“He’s great,” raved “Elephant Man” co-star Kate Burton, the daughter of Mathias’ much-loved countryman, Richard Burton.

“He’s very good at telling you what you need to know at the very minute you need to know it,” she told The Post, “which is kind of scary, but if you give over to it, it’s very enlivening.”

Equally enlivening, in its way, was Mathias’ direction of his former lover.

Soon after they broke up, McKellen starred in a benefit performance of “Bent,” Martin Sherman’s play about gays in Nazi Germany.

“We had terrible, terrible fights,” Mathias sighed. “Awful! We must have been mad, both of us. But now it’s different.”

Indeed. Last fall, Mathias directed McKellen and Helen Mirren in Broadway’s “Dance of Death” without a hitch – except for a few tense moments in previews.

“Ian was very tired that day, and while I’m usually democratic, I was cracking the whip when he wanted to discuss something,” Mathias recalled.

“He made some snide remark and I got angry. Helen came in with her kitten face on and said, ‘Now, now, boys – separate!’

“Apart from that,” he said, smiling, “it was very smooth.”