The Game Of Thrones star has revealed she survived a potentially fatal stroke shortly after filming the first season of the hit TV show.
The British actress, who rose to fame playing Daenerys Targaryen in the fantasy TV series, has spoken for the first time about the life-threatening experience and having surgery to avoid a potential second.
Writing in The New Yorker, the 32-year-old recalled getting a headache at a gym in north London in 2011 before collapsing in the toilets.
She said: "I reached the toilet, sank to my knees and proceeded to be violently, voluminously ill.
"Meanwhile, the pain - shooting, stabbing, constricting pain - was getting worse.
"At some level, I knew what was happening - my brain was damaged."
Clarke had suffered a subarachnoid haemorrhage - a life-threatening type of stroke caused by bleeding in the brain.
She was 24 years old at the time and successfully underwent a three-hour surgery. Despite surgeons managing to operate without opening up her skull, Clarke was unable to remember her name when she woke up.
She wrote: "My full name is Emilia Isobel Euphemia Rose Clarke. But now I couldn’t remember it.
"Instead, nonsense words tumbled out of my mouth and I went into a blind panic. I’d never experienced fear like that - a sense of doom closing in."
Clarke eventually recovered and was able to return to work - but before she left hospital, doctors warned her that she had a second, smaller aneurysm on the other side of her brain which would need to be monitored.
Two years on, after finishing season three of Game Of Thrones, a scan showed the growth had doubled in size and would have to be operated on.
That operation in 2013 failed, and she was rushed into another surgery which required surgeons to cut into her skull - some of which has been replaced with titanium. She wrote that she has been left with a scar "that curves from my scalp to my ear".
Clarke's decision to break her silence over her health problems comes as she launches her own charity, SameYou, aimed at supporting young people with brain injuries and helping them to access resources.
"I know from personal experience how important it is when recovering from brain injury to receive the best rehabilitation care," she said on SameYou's Instagram.
© Sky News 2019