Emilia Clarke, who plays Daenerys Targaryen on HBO’s “Game of Thrones” wrote an emotional article in which she revealed that she had two brain aneurysms, one in 2011 after filming the first season of the show and the second in 2013, after filming the third season.

Clarke revealed in a long op-ed for The New Yorker that she began working out with a trainer to relieve stress from the attention she was going to get as Daenerys Targaryen. She “felt as though an elastic band were squeezing my brain” during a workout in London.

“I made it to the locker room. I reached the toilet, sank to my knees, and proceeded to be violently, voluminously ill,” Clarke recalls. “Meanwhile, the pain — shooting, stabbing, constricting pain — was getting worse. At some level, I knew what was happening: my brain was damaged.”

Clarke claimed she concentrated on “lines from Game of Thrones” to help her cope with the discomfort and nausea, as well as to keep her mind active.

Clarke was sent to the hospital when a woman in the adjacent stall noticed she needed assistance. She remembered the ambulance sirens, someone telling her her pulse was weak, her spitting up bile, and someone calling her parents on her mobile phone.

She’d suffered a subarachnoid haemorrhage (SAH), which is a rare sort of stroke caused by bleeding on the brain’s surface.

According to the NHS, “it’s a very serious condition and can be fatal.”

Clarke says, “I’d had an aneurysm, an arterial rupture. As I later learned, about a third of SAH patients die immediately or soon thereafter. For the patients who do survive, urgent treatment is required to seal off the aneurysm, as there is a very high risk of a second, often fatal bleed. If I was to live and avoid terrible deficits, I would have to have urgent surgery. And, even then, there were no guarantees.”

Clarke said she saw early indicators of what was to come in retrospect. She thought of herself as healthy during her audition for “Game of Thrones,” albeit “sometimes I got a little light-headed, because I often had low blood pressure and a low heart rate. Once in a while, I’d get dizzy and pass out. When I was fourteen, I had a migraine that kept me in bed for a couple of days, and in drama school I’d collapse once in a while. But it all seemed manageable, part of the stress of being an actor and of life in general.”

Clarke underwent a three-hour operation that prevented the aneurysm from spreading and saved her life. The anguish she felt when she awoke was “unbearable,” according to the actress. Clarke struggled with cognitive activities like saying her name aloud in the days that followed. The actress eventually healed, but the consequences of her stroke lingered through the second season of “Game of Thrones.”

“Even before we began filming Season 2, I was deeply unsure of myself,” Clarke writes. “I was often so woozy, so weak, that I thought I was going to die… The pain was there, and the fatigue was like the worst exhaustion I’d ever experienced, multiplied by a million… On the set, I didn’t miss a beat, but I struggled. Season 2 would be my worst. I didn’t know what Daenerys was doing. If I am truly being honest, every minute of every day I thought I was going to die.”

Clarke went in for a brain scan after concluding Season 3, and physicians informed her that the tumor had doubled in size and that it needed to be addressed. The next operation was arranged, but it did not go as planned.

“I had a massive bleed and the doctors made it plain that my chances of surviving were precarious if they didn’t operate again,” Clarke recalled. “This time they needed to access my brain in the old-fashioned way–through my skull. And the operation had to happen immediately.”

Aneurysms are deadly in roughly 40% of occurrences, according to the Brain Aneurysm Foundation, and slightly over 60% of those who survive have lifelong neurological deficits. A brain aneurysm kills about 15% of patients before they reach the hospital.

Clarke claimed she suffered from anxiety and panic attacks while recovering from the second procedure and felt like a “shell of [herself].”

The actress closed by saying that her health has healed “beyond [her] most unreasonable hopes” in the years following her trauma and is now at “100%.”