The actor, 35, has previously spoken about having had brain aneurysms in 2011 and 2013 while she was employed as one of the main stars in the hugely popular TV adaptation of George R.R. Martin's books.
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Clarke, who played Daenerys Targaryen in Game of Thrones from 2011 to 2019, said that she was lucky to have survived her health problems, but had missing parts to her brain.
Speaking on BBC One's Sunday Morning, she said of her brain: "There’s quite a bit missing! Which always makes me laugh.
"Because strokes, basically, as soon as any part of your brain doesn’t get blood for a second, it’s gone. And so the blood finds a different route to get around but then whatever bit it’s missing is therefore gone."
Although she appeared lighthearted about her condition, Clarke explained that she knew how serious the aneurysms could potentially have been for her.
She said: "The amount of my brain that is no longer usable – it’s remarkable that I am able to speak, sometimes articulately, and live my life completely normally with absolutely no repercussions.
"I am in the really, really, really small minority of people that can survive that."
Clarke launched her own charity, SameYou, in 2019 to support others recovering from brain injuries.
While Game of Thrones has finished, a prequel spin-off series, House of the Dragon, is due to begin later this year, concentrating on the history of the Targaryen family.
It isn't the only spin-off show in the works, as it was recently announced that fans could also look forward to a new series about popular character Jon Snow, played by Kit Harington - who Clarke hinted may well return for it.
She told BBC: “He has told me about it. And I know it exists. It's happening.
"It's been created by Kit as far as I can understand, so he's in it from the ground up. So what you will be watching, hopefully, if it happens, is certified by Kit Harington."
However, asked whether she would come back to her own role in the fantasy series, she answered: "No, I think I'm done."
Watch: Emilia Clarke confirms Kit Harington's Game of Thrones series 'is happening'