Henry Winkler played a key role in helping Sylvester Stallone make the original Rocky. Written by Stallone with the actor also starring as the titular boxer, the iconic sports movie was released in theaters to great success in 1976. It would simultaneously spawn a highly successful franchise while launching Stallone's career as a Hollywood star.

The story of how the Barry actor came to get involved with the creation of the iconic boxing movie was revealed by Henry Winkler on Wednesday night's edition of The Tonight Show. At the time, Winkler was starring as the Fonz on Happy Days when his friend, a then-unknown Sylvester Stallone, asked him to pass along a script he wrote to the bosses at ABC. The network actually did buy the script, though Winkler had to essentially beg to get it back after they wanted to rewrite it with a new screenwriter.

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"[ABC] liked the script, so I sold them the script," Winkler recalled. "And I called Sly and said, 'We sold the script!' Then ABC called and said, 'We want to change the writer.' I then called Sly and said, 'We sold the script, [but] they want a new writer.' And he said, 'Henry, don't let them do this to me!' I said, 'All right. Absolutely.' I went back to ABC. I said, 'I know this is strange. Here's the money. I need the script back.' They said, 'We don't do that.' I said, 'This time, I am begging you. Please.' I got the script back. I gave it to Sly and said 'It's all yours.' And a year later, it turned out to be Rocky."

Following rejections from other studios, United Artists was the production company that picked up Rocky. Stallone also had to convince the producers to let him play the lead role as well, otherwise the deal would have been off the table. They ultimately agreed, and the rest is cinematic history. On a budget of less than $1 million, Rocky would pull in $225 million at the box office, which equates to more than $1 billion in today's money. Because Stallone was so perfect for the role, it seems unlikely it would have been as big of a success if someone else played Rocky.

These days, Stallone is still heavily ingrained in the Rocky franchise. He has been working hard on releasing a new director's cut of Rocky IV, one of the most popular installments of the franchise. The new cut, dubbed Rocky vs. Drago - The Ultimate Director's Cut, will include new footage which Stallone says more aligns with his own creative vision of the movie. This also means getting rid of Paulie's robot, one of the more controversial aspects of the story.

Meanwhile, the franchise continues with the Creed spinoffs as well. Michael B. Jordan is currently preparing to make his directorial debut with Creed II that will also see him returning as Adonis Creed. Stallone will not be back as Rocky in that sequel, though he has recently revealed he has another sequel idea in mind that will put the Italian Stallion back in the main role. He also wants to make a prequel series set before the original Rocky.