The Cheers actor checked into a Chicago medical centre on Sunday (October 28) when he suddenly fell ill, according to the Chicago Sun-Times.
Wendt's ill-health has led him to drop out of a stage production of The Odd Couple opposite former Saturday Night Live star Tim Kazurinsky.
The Odd Couple director BJ Jones told the newspaper that Wendt will be greatly "missed" in the upcoming play.
"George is family to us at Northlight and we wish him well for a complete and speedy recovery. He will be missed in the rehearsal room and on stage," Jones commented.
Wendt remains under a doctor's care, but is expected to make a full recovery.
He famously played Norm Peterson on the classic sitcom Cheers from 1982 to 1993.
The actor also made frequent appearances on Saturday Night Live and Late Night with Conan O'Brien in the 1990s.
Watch George Wendt in a Late Night with Conan O'Brien appearance below: