The 47-year-old singer was taken to hospital on Friday complaining of a severe headache.

Doctors later found evidence of bleeding onto the surface of the brain stem.

According to a statement on Michaels’ official website, the singer will undergo more tests to try and locate the source of the bleeding.

“Once again we can't thank everyone enough for all the well wishes and prayers being sent Bret's way,” the statement said.

“As of now Bret remains in ICU (Intensive Care Unit) under 24 hour surveillance. Further testing this week will help locate the source of the bleeding.”

Last week, Michaels had his appendix removed during an emergency operation at a private clinic.

Although well known as Posion’s frontman, the singer is also famed for his appearances on the reality shows Rock of Love and Celebrity Apprentice.

(by Jason Gregory)