<http://schema.org/articleBody>
"Warner Bros Records chairman Rob Cavallo has admitted that Green Day frontman Billie Joe Armstrong could be in rehab for some time. Armstrong checked into a treatment centre to get help for substance abuse in September after an on-stage outburst at the iHeartRadio festival.  Cavallo has now told Rolling Stone that Armstrong&amp;#039;s stint in rehab is &amp;quot;no joke&amp;quot;. &amp;quot;He&amp;#039;s under medical supervision for a while to get him clean,&amp;quot; he said. Cavallo - who has previously produced Green Day albums - added that he has no idea when Armstrong will be able to leave the centre. &amp;quot;His doctors are still evaluating,&amp;quot; he said. &amp;quot;All I can say is I don&amp;#039;t know if we&amp;#039;ll see him before or after Christmas. It&amp;#039;s basically undetermined when he&amp;#039;ll be back.&amp;quot; Green Day recently cancelled their appearance at the Voodoo Music + Arts Experience Festival due to Armstrong&amp;#039;s time in rehab and will be replaced by Metallica. Watch the video for Green Day&amp;#039;s &amp;#039;Troublemaker&amp;#039; below:      "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.digitalspy.com/music/news/a430879/green-days-billie-joe-armstrong-could-be-in-rehab-beyond-christmas/>