Joe Manganiello spent "months and months heavily medicated" during a lengthy battle with a "deadly mystery illness".

The Magic Mike actor has written a memoir, Bloodlines, in which he will detail "a cascade of autoimmune-related illnesses" which affected his skin, thyroid, eyes, lungs and digestive system but before the release of the tome, he has reflected on the years of unsuccessful treatments he undertook, which left him "mutilated" and at times unable to walk.

He said in an Instagram reel: "For the better part of the past decade -- most people don't know this -- but I suffered in silence, battling a deadly mystery illness, and other than a very small circle of family and friends, I hid it from the rest of the world, and until recently hadn't really shared what I'd gone through."

Joe, 49, consulted "the best doctors in the world" but their interventions only worsened his issues.

He said: "All their attempts to treat it with high-powered biological drugs only exacerbated my symptoms and then unlocked a host of brutal side effects that winded up plaguing me for years.

"And then in attempts to buy myself time. I underwent very serious operations and procedures that mutilated parts of my body and left me so weak at times that I couldn't stand up or walk.

"I spent months and months heavily medicated while dealing with excruciating bouts of chronic pain."

The True Blood star noted Bloodlines - which will be released in October - takes a deep dive into his family history as he sought answers to his health struggles.

He said: "Maybe what happened to me wasn't random. And that in order to heal, my mind, my body, my spirit all had to align and I needed to become open to some really radical and unorthodox techniques and ideas that lie beyond the boundaries of western medicine.

"If you're out there and you're suffering, there's hope."

As traditional medicine failed to provide answers, Joe turned to shamans, pagan rituals, ancient myths, long-lost family records and the rebirth of his own spirituality, according to the book's synopsis.

Joe, who underwent a life-saving organ amputation, recently described his struggles as "brutally difficult".

He told People magazine: "It was the most brutally difficult time of my life, one I wouldn't wish on my worst enemy, but also my greatest adventure.

"I hope that what I went through on this journey can give readers hope that answers and healing may lie for them on the other side of whatever they are fighting through. The process of writing this book gave me the gift of perspective that helped me to see that my suffering was a cocoon from which I would emerge forever changed."