Production of Channel Nine's reality series The Block All Stars has been disrupted after a contestant collapsed at the show's Bondi building site and was taken to hospital.
Mark Bowyer, 55, who with best mate Duncan Miller formed the team known as 'The Two Fat Tradies' in The Block's third season, had been at one of the new homes when he started feeling ill, a series insider said.
An ambulance was called and he was taken to Prince Of Wales hospital for examination.
"Block All-Star (contestant) Mark Bowyer, who was conducting an interview early on Monday morning, complained of dizziness and feeling "not quite right"," a spokesman for Nine confirmed.
"Immediately, foreman Keith (trained in first aid) saw to him and ordered an ambulance.
"Minutes later he was taken to hospital where they performed a series of tests. He was released that afternoon with orders to rest."
Bowyer and Miller became instant fan favourites when they took part in The Block in 2010 - marking the show's return after a six-year absence - for their laid-back attitude and the fact they brought a pie warmer with them into their Vaucluse unit.
During the series the pair often complained of the stressful workload brought on by the hectic pace of 24/7 restoration, amplified by the fact they were older than most other contestants.
They eventually came third in the competition when their unit sold for $907,000, from a reserve of $860,000.
Since then, they had used their fame to promote a footpath safety campaign for Guide Dogs Australia, offered renovation tips on Nine's website and were part of the construction team that built XXXX (Fourex) Island, a mini-resort on a small island on the Southern Great Barrier Reef as a promotion for the iconic Queensland XXXX beer.
Filming of The Block's sixth season, the tenth anniversary of the renovation franchise, began on October 12 with Bowyer leaving 45 days into the shoot.
In his absence the show's host and experienced builder Scott Cam has stepped in to assist Miller with their current rebuild, as has Jenny, Miller's wife.
Nine has said that if possible, father of four Bowyer will not be permanently replaced.
"We are of course first and foremost concerned about his health and are waiting to see if and when the doctors say he can come back to the show," a spokesman said.