The hugely popular children's group The Wiggles is expected this week to announce the departure of its lead singer because of a serious illness, media reports said Wednesday.

The Australian supergroup has reportedly scheduled a press conference for Thursday in the western city of Perth to make a "major announcement relating to members of the group," according to the Sydney Morning Herald, Australian Associated Press and the online edition of Sydney's The Daily Telegraph newspaper.

The reports said the group was likely to announce the departure of the "Yellow Wiggle," Greg Page, who has been frequently absent from touring since undergoing a double hernia operation in December.

The 34-year-old known for his bright yellow T-shirt has been undergoing medical treatment since June after experiencing fainting spells and lethargy, the reports said.

Calls to the group's publicist were not immediately returned Wednesday.

The Wiggles were Australia's top-earning entertainers last year, ahead of No. 2 AC/DC and No. 3 Nicole Kidman. The four men in brightly colored T-shirts, accompanied by a cast of characters including Dorothy the Dinosaur and Wags the Dog, grossed $39 million last year.

Page, who was replaced by an understudy when he pulled out of The Wiggles' U.S. tour in July, reportedly said he needed to rest and seek medical advice for the fainting spells.

"I have had numerous bouts of this over the past eight months but they are getting more frequent, and more concerning," he was quoted as saying by The Daily Telegraph. "So I have decided that I must go home, rest and seek further medical advice to assure myself that I will be OK for future tours."

Publicist Dianna O'Neill told The Sydney Morning Herald that doctors had not been able to identify Page's illness.

Page helped found The Wiggles in 1991 after he and two other members met while studying early childhood education at Sydney's Macquarie University.

The group has franchised its enormously popular recipe to several non-English speaking countries, including Taiwan.