A spokeswoman for the Las Vegas venue where the veteran comic frequently performs said that Lewis had not collapsed, as reported, but had merely become "dizzy".

He was watching the screen clips of an earlier show of his behind the stage when he just sat back

Steven Alan Green Organiser

Candi Cazau said Lewis was in his dressing room at the theatre - where he first appeared with Dean Martin some 50 years ago - when he "got a little dizzy".

The spokeswoman added that "everything checked out OK" when the 76-year-old entertainer was treated by an ambulance crew at the stage door.

Resting

Sunday's audience for the show High on Laughter, organised for drugs charity Turning Point, was told Lewis would not be performing because he was unwell.

He has since been resting at his London residence.

Lewis was given a lifetime achievement award at the 1999 Venice Film Festival

In a statement, the show's producers Steven Alan Green and Tamsin Hollo wished him "a speedy recovery".

"He was watching the screen clips of an earlier show of his behind the stage when he just sat back," Mr Green said later.

Lewis's wife SanDee, speaking from Las Vegas, said her husband, despite suffering from ill-health, had not taken a turn for the worse.

"He has not been taken ill. There is no change in his condition," she said.

Diagnosed

Lewis has been plagued by ill health for the last two decades, battling prostate cancer, pulmonary fibrosis and spinal meningitis.

Lewis was diagnosed with spinal meningitis while on tour in Australia in 2000, and takes steroids to help battle pulmonary fibrosis, which is an increase of fibrous tissues in the lungs.

I have jet lag from the 1960 trip

Jerry Lewis before being taken ill

The pain has caused him to contemplate suicide, according to an interview in Monday's Daily Mirror newspaper.

"In April it got so bad that it forced me to get a gun and seriously think about putting it in my mouth," he said.

In 1982, he was declared clinically dead after suffering a heart attack.

Lewis was recently confined to a chair while hosting most of his 37th telethon for the Muscular Dystrophy Association.

The telethon raised a record $58.3m (�37m) for the charity.

He complained of tiredness earlier on Sunday when he was unable to travel to a BBC radio studio for an interview, instead conducting it over the phone.

He told BBC London 94.9FM that he made the trip to London on Saturday just to do the benefit show, and joked: "I have jet lag from the 1960 trip."

He added: "There's just something about London that gives you a charge, with the exception of Fleet Street of course."