EXCLUSIVE: Elvis' Dark Secrets Laid Bare 50 Years Later – How The King's 'Drug Addiction' Was Kept Under Wraps by Manager Colonel Tom Parker Despite Their Volatile Relationship

Elvis Presley made a wicked deal with the devil: He kept his mouth shut about his manager Colonel Tom Parker's destructive gambling addiction because Parker was keeping Presley's drug habit hush-hush, RadarOnline.com can reveal.

Music historian Peter Guralnick's blockbuster new book, The Colonel and the King, reveals that the two had a volatile relationship and attempted to split several times, including one infamous instance – when Presley lashed out at Parker from the stage while performing at the Hilton Hotel in Las Vegas in 1973.

But their shared secrets held them together.

"Each of them was aware of the other's addiction, the other's failures, and neither one of them was going to bring up the other's failure for fear that the other would then bring up his own – and they were stuck," explained Guralnick.

"The colonel became in a sense not a tragic figure, because he was a life force overall, so full of vitality and creativity," added the author, "but I came to see those last years with Elvis as a linked tragedy, in which each of them has their own addictions, and I just didn't see that before."

Priscilla Presley saw a lot.

On the 45th anniversary of Elvis' death, she said the hardest part of watching Baz Luhrmann's biopic Elvis was reliving his relationship with Parker. She believes Elvis wanted to take his career further than music.

She added: "He wanted to do movies, serious movies, and Colonel Parker probably should have stayed a publicist. He didn't take Elvis where he wanted to be, and that was hard because I lived it. I lived the arguments that they had,

"I lived Elvis trying to explain he didn't want to do the movies with all the girls and the beaches and everything, that he really wanted to do serious things. So living that, with him, and watching the movie, it brought back a lot of memories."

How much she knew about their twisted alliance is unknown.

"She may have known and turned the other way, or Parker and Elvis could have been so good at keeping their secret – in order to feed their addictions – that it's possible she knew absolutely nothing," said a source.

"If she had had a clue, maybe things would have turned out differently. Maybe Elvis would have broken free from Parker and gotten help."

After Parker's death in 1997, Priscilla attended his funeral and even delivered a lighthearted eulogy, suggesting there's a level of complexity in how she viewed him. She also reportedly noted Elvis was willing to pay Parker 50 percent of his earnings to manage him. That could point to how severely Elvis was in the throes of addiction," said the source.

"It was as if Parker was his dealer, in the figurative sense, and their secret ended up being a deadly one."

Guralnick believes the King knew another bombshell secret about the Colonel and kept it under wraps: Parker was born Andreas Cornelis van Kuijk in Holland and came to the United States as a stowaway.

That hush-hush information, combined with Elvis' drug habit, prevented the King from taking his show on the road outside the United States. Elvis' close Memphis Mafia buddies were convinced that he desperately wanted to tour the world, but he was sure Parker feared deportation – while the Colonel was actually concerned about security... and Elvis' drug addiction.

"Everybody thought he meant you can't get armed guards to protect Elvis from the crowds," explained Guralnick. "That wasn't what he meant at all – he meant the security to keep Elvis from getting busted. Who was going to carry the drugs? Who was going to carry the guns?"

Their secrets were safe with each other.