The Happy Days star was 31 when he was first diagnosed with the learning condition, and he works tirelessly to raise awareness of the disorder.
He is backing the Evening Standard's literacy campaign, and he visited schools in the U.K. capital to encourage youngsters to seek help from teachers if they are struggling to read.
Winkler says, ""When I talk to pupils I tell them of my journey through school. I ask if anybody has trouble in school the way I did. Only one or two raise their hands.""
The star admits he was in the ""bottom three per cent academically"" and his revelation appears to have had a positive effect on the students: ""When I ask the question at the end, all 300 kids put their hands up. I do this because at that age I wanted someone to say it was going to be OK.""