Henry Winkler co-starred with Sly Stallone in Lords of Flatbush before he rocketed to fame as Fonzie on Happy Days. Most fans know that Winkler credits Stallone with his take on the Fonz. Winkler has a real admiration for Sly. Check out this section of Winkler’s interview with the Archive of American Television and you’ll see, but first a quote from the interview…
“I studied Sly, Sly Stallone. He was big, beefy… what Sly really was inside was funny, witty, unbelievably articulate and a brilliant writer… the tenderness inside… just a fabulous human being… The shame of Sly is you’ve never witnessed his wit. You’ve never seen him play that kind of humor. He is so fast and so funny!
Source: MeTV – Henry Winkler once explained how Sylvester Stallone inspired Fonzie’s voice.