According to the rocker-turned-reality-star, the troubled actor - who went on a reported drink and drug-fuelled rampage, smashing up his room at the New York Plaza hotel last October and terrifying a porn star - learned everything he knows about wreaking havoc from him.
Bret said: "I professionally showed [Charlie] how to bust a hotel room. Because he wasn't doing a good job at it first.
"He was kind of learning. I said, 'You gotta really let it out man! You gotta let it out and bust this stuff.' "
The 'Every Rose Has its Thorn' singer - who became friends with Charlie after they were introduced by a mutual Penthouse Pet pal years ago and directed him in films 'A Letter From Death Row' and 'No Code of Conduct' - also revealed the former 'Two and a Half Men' star taught him how to profit from the movie industry.
He told 'Access Hollywood': "He showed me how to do films and make money, and I showed him out to lose a lot of money by smashing up hotel rooms."
Bret went on to say that the pressures of fame may be to blame for Charlie's recent bizarre behaviour, which has seen him frolicking with numerous porn stars and claiming to drink tiger's blood, and is adamant despite his apparent problems he's really a "great guy".
He added: "There's a lot of frustration in this business that we do, you're under the microscope. He's going out there and doing his thing, I don't know if you win or lose. He's always been a good friend to me.
"I know right now there's a lot of crazy stuff going on, but he's a great guy. I don't know if he's winning or losing, maybe he's just spilling out what he's going through right now."