"When I make my first entrance, I'd like to come out of the door carrying a cane and then walk toward the crowd with a limp," Wilder wrote in a letter to director Mel Stuart.
"After the crowd sees Willy Wonka is a cripple, they all whisper to themselves and then become deathly quiet. As I walk toward them, my cane sinks into one of the cobblestones I'm walking on and stands straight up, by itself; but I keep on walking, until I realise that I no longer have my cane. I start to fall forward, and just before I hit the ground, I do a beautiful forward somersault and bounce back up, to great applause."
When asked why he was so adamant about this scene, Wilder replied, "From that time on, no one will know if I'm lying or telling the truth".
NAUGHTY OOMPA LOOMPAS
According to Paris Themmen (who played Mike Teevee) the 10 Oompa Loompas were "notoriously mischievous" behind the scenes.
"They were often drunk after a day's shooting," Themmen said during a Reddit Ask me Anything session.
"We all stayed in a hotel together. In those days, when you wanted to have your shoes shined, you'd leave them outside of your hotel room door. One night the Oompa Loompas grabbed all the shoes, tied the laces together, and left them in a pile to be found in the morning."
YOUNG STARS' SALARIES
Themmen was paid $US500 per week for the nine weeks of filming, as well as a free trip with his family to Germany where the movie was filmed.
In a Reddit AMA, he revealed that he also gets the occasional cheque in the mail for his work in the film.
"I get residuals when the film is shown on network TV, not for cable, DVD, or VHS sales," Themmen said.
"The contract between the signatory producers and SAG that covered those ancillary markets was signed six months after I signed my contract. Ouch."
BIZARRE THEORY
Some people believe that Willy Wonka is actually a murderous villain who uses deceased children to make his chocolate.
Here's their argument: Wonka rigged the golden ticket competition to ensure that only children won. Then he set up elaborate scenarios once the children were inside his factory to test their morality. Could Augustus Gloop resist a river of chocolate? No. Could Violet Beauregarde resist a revolutionary piece of chewing gum? No.
Also, the Oompa Loompas were in on the scam because they just happened to have a song and dance routine tailored to each kid's death.
And finally, ever notice how each of the vehicle's shown in the flick only have the exact number of seats required for the remaining kids?
"They wanted to film our initial reactions to the Chocolate Room set, so it was a closed set until they opened the door, let us in, and we saw the river running, the waterfall flowing, 360 degrees of a panoramic chocolate wonderland," Themmen said.
The same goes for when the golden ticket winners take that terrifying boat ride in the tunnel with Wonka.
"The director did not warn us what was coming in this scene," Themmen said.
"Gene (Wilder) is so great in this scene, and it didn't take much acting on our part to play 'What the f**k is wrong with this guy?'"
WHERE'S CHARLIE NOW?
"I was offered a three-picture deal with the studio (after Willy Wonka & the Chocolate Factory), but I decided not to pursue acting," Peter Ostrum (who played Charlie Bucket) said to Express in 2014.
"Looking back, my pay cheque was paltry, but it was during filming that I really became interested in medicine. So I bought my first horse with my earnings and that started my current career path as a vet."