The 26-year-old actress suffers from the learning disability - which affects sufferers ability to read - and when she was growing up it was having a negative impact on her studies.
But young Keira idolised `Nanny McPhee` star Emma and her mother Sharman MacDonald - who worked with Emma on the 1995 film `Sense and Sensibility` - used her daughter`s adoration to inspire her to beat the condition.
The `Atonement` star was given a copy of the `Sense and Sensibility` script by her playwright mum to try and read and told her giving up was not an option.
Keira revealed: "I`m a huge fan of Emma Thompson, huge! "I was - am? - dyslexic and the way my mother got me over it was to say, `If Emma Thompson couldn`t read, she`d make sure she`d get over it. So you have to start reading because that`s what Emma Thompson would do.` "
The actress is one of Hollywood`s hottest young starlets and can next be seen in `A Dangerous Method` - in which she plays a troubled patient and then student of psychoanalyst Carl Jung, who her character falls in love with.
Despite her big screen success, Keira has to endure criticism - especially, she claims, in her native UK - and she admits the attacks against her work do get to her on occasions.
In an interview with the March issue of Britain`s GQ magazine, she said: "The Americans are generally a lot more supportive. They generally like the work I do a lot more than they do here (in the UK). It is what it is, I suppose. It could just be that I`m not to a lot of people`s tastes which is fine. Well, it`s not, obviously. You want to be to everyone`s taste. But I think it`s better to do your own thing rather than try to please everyone and just be this mushy thing in the middle. Sometimes it`s like water off a duck`s back and sometimes it really hurts. Then you go away and cry for an hour or so, and then you pick yourself up again."