The film written and directed by Stephen Merchant is based on the life of WWE superstar Paige.
Vaughn is "playing a man who I know all too well and those of you who follow wrestling history know well too," Johnson wrote on Instagram.
"The 80's wrestling star who squandered his money and opportunities because he didn't have the capacity to handle his fame. One bad decision after another, but these days he owns his past actions and does everything he can to give back to the wrestling business he loves," he added.