Details surrounding the rocker's condition have not been released, but many friends and fellow musicians have taken to social media to inform fans of his medical emergency.

"Please join me in sending massive amounts of prayer and PMA (positive mental attitude) for Dr. Know, who is fighting for his life at this very moment," author Greg Tate wrote on "Just send all the love that you can for my brother in wires".

The guitarist, real name Gary Miller, is reportedly on life support, according to the social media posts.

A statement from Bad Brains reads: "The Bad Brains family ask that you please keep Gary (Dr. Know) Miller in your thoughts and prayers. The family respectfully ask that their privacy be honored during this time and very much appreciate all the great energy that is being sent their way."

Dr. Know appeared onstage with Foo Fighters in New York City this past summer (15). He appeared in Dave Grohl's acclaimed 2014 documentary series Sonic Highways.