Williams, 57, had already announced in a statement he was postponing upcoming performances of his ‘Weapons of Self-Destruction’ in south Florida.

However, a further statement from the veteran funnyman yesterday said he would undergo an operation to replace an aortic valve and was rescheduling nearly two dozen upcoming performances running through to May.

The statement said the tour would resume later this year.

"I'm so touched by everyone's support and well wishes," said Williams in the statement. "This tour has been amazing fun and I can't wait to get back out on the road after a little tune-up."

It was not clear when and where Williams would undergo the procedure. The Miami Herald reported earlier the comic was at a Miami hospital.

Williams was in the unnamed hospital's intensive care unit, the ‘Los Angeles Times’ added.