"The Superstar Billy Graham Just Left Us THANK YOU FOR ALL YOUR INFLUENCE On My Career," Flair tweeted.
Earlier this week, TMZ Sports reported that Graham was on life support and his health situation was described as dire, but his wife, Valerie, said she refused to remove the wrestler from life support.
"Please urgent prayers needed for my husband," Valerie said in an update on her husband's health via TMZ Sports. "The doctors wanted to remove him from life support tonight. I refused."
"He’s a fighter and his will is strong even if his body isn’t. God is our hope."
Graham was the sixth man to win the then-World Wide Wrestling Federation (now WWE) championship, defeating Bruno Sammartino on April 30, 1977 in Baltimore, Maryland and held the title for 296 days. The former bodybuilder is credited as one of the most influential wrestlers of his era, inspiring the likes of Flair, Hulk Hogan, Jesse 'The Body' Ventura and Scott Steiner.