Avildsen's son Anthony told The Los Angeles Times Friday the filmmaker died of pancreatic cancer at Cedars-Sinai Medical Center. He was 81.
"The great director John G. Avildsen Who won the Oscar for directing Rocky! R. I. P. I'm sure you will soon be directing Hits in Heaven- Thank you , Sly," Stallone wrote in an Instagram post captioning a photo of him and Avildsen on the set of 1976's Rocky.
"RIP to my friend and KK director John G Avildsen. He brought inspirational stories to us all and had a guiding hand in changing my life," Macchio tweeted, along with a collage of photos of them together, including one from when they were shooting 1984's Karate Kid.
Avildsen's credits also include Joe, Save the Tiger, Lean on Me and Neighbors.