AS THE heartthrob of Happy Days, The Fonz was rarely seen without his beloved biker jacket, administering a well-timed thump to get the jukebox working, or clicking his fingers to attract a gaggle of swooning girls.
Today, 69-year-old actor Henry Winkler is more partial to a practical purple puffa coat than leathers, and spends his downtime indulging his love of fly-fishing. But he still possesses all the charisma that made his sitcom alter ego such a hit.
He's speaking on the set of Hank Zipzer, the Yorkshire-filmed CBBC show based on Winkler's children's books about schoolboy Hank, dubbed 'The World's Greatest Underachiever'.
The books, co-authored with writer and film producer Lin Oliver, are inspired by Winkler's own experiences growing up with dyslexia (with the New York setting switched to the UK for the TV version).
While trucks whizz around him, shifting camera equipment for the upcoming second series, Winkler – who plays kindly music teacher Mr Rock – is brimming with enthusiasm for the show and its positive message.
"What I want every child to know is you're not defined by school. No matter how you learn, you have greatness inside you," says the star, who wasn't diagnosed with dyslexia until he was in his 30s.
"I was told I would never achieve. I've had a pretty extraordinary career and spelling is something that I can't do for all of my life."
Despite his learning struggles, and regular unfortunate run-ins with his teachers and parents, loveable Hank – named after Winkler and a woman named Zipzer who lived in his apartment block in the Big Apple – is an eternal optimist.
"Hank's the most positive guy you've ever met. His cup is half full – he just spills his glass everywhere..."
Winkler credits a music teacher – the real-life Mr Rock – with giving him some much-needed encouragement at school.
"Mr Rock said one sentence to me. He said, 'Winkler, if you ever do get out of high school, you're going to be great'. And I held on to that sentence like Leonardo DiCaprio held on to a piece of wood when he fell off the boat [in Titanic]," he says, laughing.
Another Hank Zipzer character, the fearsome Miss Adolf ("the worst teacher on the planet", played by Alan Partridge star Felicity Montagu), is also inspired by Winkler's difficult school days.
"She's not alive any more, God bless her. What a mean woman," Winkler recalls with a sigh. "Felicity plays her with more humanity than she actually had; I raised my hand in the fourth grade to go to the boy's room, I'm still waiting for her to call on me. Any time now!"
After appearing in school productions, Winkler studied at the Yale School of Drama and had some minor TV appearances before being cast as Arthur 'Fonz' Fonzarelli in 1973. Smooth-talking Fonzie proved a huge hit with viewers, and Winkler remained on Happy Days until it finished a decade later.
Since then, the father-of-three has produced and directed, and also appeared in films including Scream (1996) and Adam Sandler's The Waterboy (1998), and TV comedies Arrested Development and Parks And Recreation.
Since the first Hank Zipzer tale was published in 2003, Winkler has toured the world, promoting the book and spreading its message. In 2011 he was made an honorary OBE for his work on dyslexia.
He's been making the most of his downtime in Yorkshire on breaks from filming, with cinema and fishing trips.
"I'm blessed. A lot of men my age are sitting at home waiting for the phone to ring, and I'm having this wonderful life, being able to do what I dreamt of doing when I was seven," he admits.
"Last night, I'm having a sandwich in my hotel, a man comes up and says, 'My daughter read Hank Zipzer, every one of them. She just graduated university with honours. She's dyslexic but she got strength from Hank'. Oh my, what a compliment that is."
Hank Zipzer returns to CBBC on Thursday August 13.
