The front man of glam rock band Poison was rushed to an undisclosed hospital on Friday with a severe headache. Doctors diagnosed a massive subarachnoid hemorrhage, or bleeding at the base of his brain stem.

A statement issued on Sunday by publicists for the 47-year-old singer said he was still under 24-hour supervision and in critical condition and that doctors were trying to locate the source of the bleeding.

Bret is a fighter and we are hopeful that once all is complete, the slurred speech, blurred vision and dizziness etc will be eliminated and all functions will return to normal, the statement added.

Michaels rose to fame in the 1980s at the helm of Poison, whose hits included the ballad Every Rose Has Its Thorn.

He was diagnosed with diabetes as a child and just last week disclosed he had an emergency appendectomy earlier this month. In a blog entry, he called it a wake-up call to be a little bit more diligent on keeping control of my health.

In recent years, Michaels found fame as a reality TV star in such shows as VH1's dating contest Rock of Love and on the current season of The Celebrity Apprentice.

His latest album Custom Built is due to be released later this year and he recently recorded a song with Disney starlet Miley Cyrus.

On The Celebrity Apprentice, which was filmed several months ago but is about halfway through its broadcast run on NBC, Michaels has raised $100,000 for his charity, the American Diabetes Association, and is a strong contender to win.