In an interview with Pulse Radio, the 'School's Out' singer contended that he let his own addiction battle affect his concert performances.
"I relate to him on one level," Cooper said. "When I was an alcoholic, I was the most functional alcoholic there was."
He added: "In other words - I was drinking too much, everybody knew it, everybody saw that I was, you know, getting sick - but, when it came to doing my job, I was dead-on, when it came to doing a show."
Cooper also expressed his belief that Sheen was unfairly fired from the hit CBS sitcom.
"If he's showing up to do his job on that show, and he's straight, and he knows his lines, and he's funny, and he's not a problem - I don't know how they can stop the show. He's actually fulfilling his contract," the rocker remarked.
The musician, who has notched up six US platinum-selling LPs, was recently inducted into the Rock and Roll Hall of Fame.
It was announced this morning that Sheen has added 12 more shows to his upcoming 'My Violent Torpedo Of Truth/Defeat Is Not An Option' tour.