Leif Garrett was the biggest teen idol on the planet in the 1970s before the darker side of fame grabbed hold of him. For years, the former pop star battled with intense drug addiction. Now Garrett, 51, is able to reflect on how his stardom went south, and advise young stars like Justin Bieber how not to follow in his footsteps.

FOX411: What advice do you have for Justin Bieber?

Garrett: Do not believe your own publicity. Sussing out who your real friends are is full-time work. Every scum bag, every drug dealer, every chicken hawk wants a piece of you.

FOX411: Do you notice similarities between Bieber and yourself when you were his age?

Leif Garrett: I don’t know. I mean our circumstances are quite different. This is something he really wanted to do and he achieved it. I was in acting. When you’ve got that sort of power at that young age, and everything at your doorstep, you put out that bad boy image. At that age, testosterone, hormones, all of the money, you see what else you can get away with. He’s also doing a lot of charity work.

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FOX411: What’s the craziest thing you ever did or bought as a kid with unlimited money and power?

Garrett: Too many to speak of. I did plenty of crazy stuff, but I did a lot of charity stuff.  You can’t stop. You want to continue to taste, and sometimes that’s crazy, stupid things. The craziest good thing I did was fly Nicolette Sheridan to New Zealand and bought a diamond. We were toasting her being there with champagne. I dropped the diamond into her glass and she almost swallowed the diamond.

FOX411: Do you and Sheridan keep in touch still?

Garrett: We don’t talk that often as we used to. We’ll always be connected.

FOX411: Are there parallels between your past relationship with Nicolette to the on-again/off-again relationship with Justin and Selena Gomez?

Garrett:  I did notice. He (Bieber) rented out the Staple Center for her. Fame, money is what tore us apart. Nicolette just started modeling. My career was pretty much there. We would get along great or clear rooms. That’s the whole thing with Justin and me. There was no in between…really good or really naughty.

FOX411: What do you attribute to your downward spiral at the peak of your fame?

Garrett: The hardest thing was the music I was doing. I had no control of the music. They wanted me to continue doing teen idol stuff. I’m really into music and a new wave was happening. The average lifespan of a teen idol is five years. You have to change musically. Bubble gum pop was good for the first time you have sex. They didn’t want to give the OK on some really good music. It was the frustration of being signed to that label. I was depressed. My heroes and A&R guys on the bus were doing drugs so I was doing drugs.

FOX411: Why do you think you beat your addiction while others like Cory Monteith fell victim to it?

Garrett: It’s a tough one to beat. It takes your soul. It’s your lover. It’s your food. I looked, like, crappy, but I was doing work just to get money to pay for it. I’ve been lucky. There’s a reason I’m here on this planet. I’m never going to hit "teen idol" again and I don’t want to. I’d rather be behind the scenes.