Bret Michaels

Bret Michaels remains hospitalized and in critical condition after doctors discovered that he suffered a massive brain hemorrhage, TVGuide.com has confirmed.

The 47-year-old singer was rushed to an undisclosed hospital late Thursday with a painful headache. After an examination, doctors found Michaels was bleeding at the base of his brain.

Bret Michaels recovering in facility for diabetics

TMZ reported late Friday that Michaels had stabilized. However, an update on his official website on Saturday disputed this report and said the singer was still in critical condition at an undisclosed location. "Further tests are being ran and information will be updated in the coming days."

Michaels' rep also said that no additional information would be available until the testing was completed.

Bret Michaels recovering after emergency appendectomy

Michaels' father, Wally Sychak, told RadarOnline he spoke to his son on Friday morning. "He sounded upbeat and positive but they had him sedated," he told RadarOnline. "But he's doing good. He sounded like my son."

Sychak said doctors had not yet determined what caused the bleeding, but believe it is related to Michaels' Type 1 diabetes. "We're all keeping our fingers crossed and saying our prayers," Sychak said. "He just needs to be quiet now and get rested."

The Poison frontman and Celebrity Apprentice star had been under doctor's supervision as recently as Wednesday, according to his website, after he underwent an emergency appendectomy on April 12. Michaels was then transferred to a private facility for diabetic patients later that week.

"I don't know how much longer I will be under medical supervision," Michaels wrote on his Fancast celebrity blog on April 17. "I've spoken to several doctors and they all seem to be impressed with the condition I have been able to keep myself in as a juvenile diabetic. But a lot of extra care needs to be taken to make sure my body heals correctly."

Celebrity Apprentice executive producer and host Donald Trump said he was "deeply saddened" to hear about Michaels, who is currently appearing on the reality series.

"My thoughts and prayers are with him and his family at this time," Trump said in a statement. "He's a great competitor and champion and I hope he will be fine."