Bret Michaels pulled out of a charity concert after he was struck down with 'severe dehydration' and influenza.
The Poison frontmant was expected to make an appearance at the XSport Fitnesss Rock 'n' Roll Chicago Half Marathon and perform for competitors at the end of the race, but he had to bow out of the event early on Sunday.
A statement from marathon organisers reads: "We are sorry to announce that Bret Michaels was not able to take the stage this morning due to a sudden bout of severe dehydration and the flu...
"The entire Rock 'n' Roll Marathon Series family wishes Bret a quick and healthy recovery and we look forward to his participation at our upcoming events."
Michaels has been tweeting fans from his sick bed to apologise for the cancellation.
In a post on Twitter, he writes: "Not only feeling bad physically, but also feeling bummed about missing the show today in Chicago. Such great fans!..."
Meanwhile, the singer has also been left saddened by the Saturday night tragedy at the Indiana State Fair, which was shut down after five fans were crushed to death and others injured when huge gusts of wind caused stage scaffolding to collapse moments before country duo Sugarland was due to perform.
Another tweet reads: "Thoughts & prayers go out to the people of Indianapolis, their families & the band @sugarlandmusic in regards to the tragedy last night."
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