I would leave a word out, a line out.

Meanwhile, the other actors would be waiting, staring at me: It was humiliating and shameful.

Everybody in the cast was warm and supportive, but I constantly felt I was letting them down.

Henry Winkler (l) in  “Guess Who’s Coming to Christmas” - ‘Happy Days’ Season Two

Henry Winkler (l) in “Guess Who’s Coming to Christmas” - ‘Happy Days’ Season TwoABC Photo Archives/Disney General Entertainment Content via Getty Images

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When Winkler was diagnosed, I was so fing angry, he writes.

All the misery Id gone through had been for nothing.

It wasnt a way I decided to be!

‘The Kings of Kings’

And then I went from feeling this massive anger to fighting through it.

Winkler has since written several best-selling books to educate others about dyslexia.

Being Henry: The Fonz… and Beyondis out Oct. 31.