The 70-year-old rock star had a "terrible" time trying to overcome his dependency on the drug, and only by replacing it with another vice was he eventually able to stop relying on heroin.
Speaking on the Club Random with Bill Maher podcast, he said: "Once you're trying to get off heroin, what do you go to? You go to something else. I started smoking crack to get off heroin."
Amazed host Bill Maher said: "Did you really?"
Billy laughed as he replied: "It worked. It worked.
"This is probably the worst advert, but it worked.
"It's kind of nasty…I liked taking drugs back then. It took me a long time to put them in the rearview mirror. At some point, I realised you had to do that."
The Rebel Yell singer - whose years of excess and struggles with addiction are documented in new documentary Billy Idol Should Be Dead - is grateful his drug use came earlier in his life.
"That's the most scary thing I think, when people start taking drugs and they're old…I'm glad I did it in my 20s or when I was a teenager…not now. You need energy to be a drug addict and I don't have that kind of energy," he said.
In Billy Idol Should Be Dead, Billy recalled how he "nearly died" ahead of his debut on UK TV show Top Of The Pops after snorting the "strongest heroin".
"I did OD and nearly died. I went to America in March 1981 and came back to the UK in triumph in 1984, after Rebel Yell. I was due on Top Of The Pops. I nearly ruined it and nobody knew," he said.
"On our return to London we met some pals and they had some of the strongest heroin, Persian Brown, I think. Everybody did a line and they all nodded out except me and a mate and we did a few more lines.
"I was basically dying. I was turning blue. So they put me in an ice bath and walked me around on the roof of the building."
White Wedding singer Idol has described coming off heroin as "one of the most awfulest experiences in the world".
"Boy George said it right when he said it's like your skeleton trying to get out of your body," he said.
"There's no quick fix. It's such a long time. You're just counting the days, the seconds, the hours. Even after six months, you still feel lousy."
18°C