By Rob Taylor

CANBERRA (Reuters) - The frontman of one Australia most successful entertainers, children's group The Wiggles, quit on Thursday to battle a rare illness.

Greg Page, the magician and Yellow Wiggle in the popular flourescent-skivvied foursome, suffers from orthostatic intolerance, a disorder which stops his heart from pumping enough blood while standing or dancing.

"I'll miss being a part of The Wiggles very much, but it's the right decision because it will allow me to focus on managing my health," Page, 34, told reporters from Perth, where the group is on tour. He had been with the group since its 1990 debut.

The Wiggles have won over children around the world with catchy songs such as "The Monkey Dance", "Fruit Salad" and "Wake Up Jeff".

Allied with simple, rousing dances and Page's magic tricks, the four have amassed a fortune from sell-out concerts and home video sales, mostly in the United States.

An April survey said the group grossed $39 million last year -- more than rock band AC/DC and actor Nicole Kidman combined -- becoming Australia's top entertainment earners.

The group -- Page, Anthony Field, Murray Cook and Jeff Fatt -- once played 12 sold-out shows at Madison Square Garden in New York, breaking Bruce Springsteen's record. Adult fans include John Travolta, Sarah Jessica Parker, Shaquille O'Neal and Courtney Cox-Arquette.

Page fell ill this year, experiencing frequent fainting spells, dizziness and lethargy. He will be replaced by an understudy.

James Thomson, who edits business magazine BRW, said Page's departure was unlikely to affect The Wiggles empire, which includes franchises in Taiwan and Latin America and which will soon extend to China and India.

"We're talking about Yellow Wiggle rather than a person's name, so you can probably substitute another yellow Wiggle and get away with it," he told Australian Broadcasting Corp. radio.

"For a lot of the new fans, the kids just turning two or three, they won't know any different."