04/12/2010 AT 7:55 PM ET
Bret Michael tried to ignore the pain in his stomach Sunday night, hoping he could make the stage for a show in San Antonio, Texas.
But by 1 a.m. Monday, the 47-year-old rocker and contestant on The Celebrity Apprentice had to be rushed to the hospital with what he thought was a severe case of the flu. Instead, he underwent an emergency appendectomy.
Michaels “remains in the hospital, is doing well and beginning the recovery process,” his rep says.
“Michaels, who has been known to perform under extreme conditions that would make most performers cancel, will unfortunately have no choice but to reschedule some of his April tour dates,” the rep adds.