Green Day's Billie Joe Armstrong has opened up about his substance addictions, admitting he "was the joke".

The frontman sought treatment for his alcohol and prescription drug dependencies after eventually melting down during Green Day's set at the iHeart Radio festival in Las Vegas last September.

Armstrong admits bandmates Tré Cool and Mike Dirnt were "scared" and "f**king pissed" after he started his long road to recovery, and the star says he also worried about the effect his hell-raising lifestyle had had on his wife Adrienne too.

He told Rolling Stone: "I'm sure that crossed her mind, that if I didn't get sober I could potentially lose all of that stuff. I could have lost the band too. I didn't realise how destructive I was. I thought everybody was in on the joke. But I was the joke."

Armstrong says his Vegas meltdown is a bunch of hazy memories at best.

He explained: "The thing in Vegas, some people love it, some people hate it. I know I'm not gonna relive that. That's a side of me I don't want my fans to ever see again.

He added: "I blacked out. I remember tiny things, getting to the venue, being backstage, trying to shake the buzz off ... People will remind me a little bit [about it now]. Or I'll see a photograph. It makes me so sick. What I said or did, that's not what really bothers me. It's the fact that it wasn't me. I'm not that person. I don't want to be like that."