Bret Michaels was hospitalized Thursday, just hours before he was due to go on stage.
The Poison frontman - who has type 1 diabetes - was admitted to a medical facility in Nashville after falling ill ahead of the band's show with Def Leppard, Motley Crue, and Joan Jett and the Blackhearts.
Sources told TMZ the 59-year-old star may have had a bad reaction to medication related to COVID-19 as a result of his diabetes.
Bret's bandmates went on stage to regrettably inform the audience they wouldn't be able to perform that evening, but they have made no further announcements about his condition.
Two years ago, the 'Every Rose Has Its Thorn' singer revealed he had been diagnosed with skin cancer and also needed surgery on his shoulder.
In a blog post on his website, he wrote: "After a very recent kickoff to the new year, physical MRI it has been brought to my attention that I have torn my right shoulder rotator cuff which would answer the question why it looks like a lump or bone was sticking out of my right shoulder.
"A little more complex I will also have to undergo a procedure to remove skin cancer that was detected after a recent biopsy."
The 'Crack A Smile' rocker recently opened up about his major health scare in 2010, when he suffered an appendectomy, brain haemorrhage, and heart surgery.
He admitted: "I dealt with a lot of health issues during that year, and by the grace of God and a lot of hard work and therapy, I'm still on the good side of the dirt and having a good time."
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