Michaels, who suffered a near-fatal brain haemorrhage in 2011, says: "My thoughts and prayers go out to Rikki. I have known for a while he was going through this tough battle.

"Although people have asked me about his health, out of respect for Rikki's wishes, it wasn't my place to speak about it until Rikki was ready to talk about it himself. He is a longtime friend and a true fighter."

Last week, Michaels hinted that Poison - who last made a public appearance together in 2013 - could play "select" dates next summer to celebrate the band's 30th anniversary.