Green Day's Mike Dirnt says Billie Joe Armstrong has had it "really rough" following his public breakdown.

After an on-stage outburst in Las Vegas last month, where Billie smashed his guitar during a foul-mouthed rant, the singer announced he would be seeking help for substance abuse.

The band, which consists of bassist Mike, singer Billie, drummer Tr Cool and guitarist Jason White, have had to postpone upcoming shows but Mike believes they can overcome the issues.

"I'm sure Billie's had it really rough. There's been very little contact between us, so I guess I'm just generalising, but it's a pretty heavy-duty process," the bassist told BBC Radio One.

"This is probably the longest time we haven't seen each other - I haven't seen Billie in weeks. It's an awkward position to be in, but we're going to pander this out. We'll get there."

Billie's breakdown came during a world tour, where the band was promoting their three new albums.

Green Day also played at Reading festival in the UK, and Mike worries the workload pushed his bandmate over the edge.

"Although we were having fun we didn't take our nose out of the book for a long time," he confessed.

"I think it catches up with you a little bit. We definitely just jumped off a moving train. There were signs of things hitting the fan. We hadn't slept in forever and Billie had definitely had the worst of it. He'd been going through his own struggles. We were there with him but you can only handle things on your own. At the end of the day when we got off the road the most important thing was my friend's life."