King told the Herald on Sunday he found himself riding a roller coaster of emotions as memories of Caden's fight for life flooded back after the tot contracted the potentially fatal MRSA infection in an American hospital.
"I just about lost it in the middle of the challenge," admitted King.
"It was if I was teleported back to how we were feeling eight years ago. I came close to shedding tears. It felt like it was yesterday."
King and his wife, Nicola, spent two months at the Los Angeles hospital bedside of their gravely ill newborn son. At the time doctors gave the then 2-week-old baby just a 10 per cent chance of living.
Caden defied the odds and is now a healthy 8-year-old.
King described it as a harrowing period in his life when he was forced to be a spectator watching his tiny son fight for his life, spending day and night in a hospital room snatching sleep on a chair.
Because of Caden's brave battle, cooking for the MKR People's Choice Challenge at Ronald McDonald House was a humbling experience. His thoughts were with the sick kids, and their parents.
"Their whole life is in shambles yet they show such strength and courage dealing with their sick children."
He said the teams involved in the Ronald McDonald House challenge enjoyed doing "something real". King and Gascoigne stayed well after the cameras stopped rolling to spend time with their VIP dinner guests.
My Kitchen Rules New Zealand has now entered the "Kitchen HQ" phase in which the remaining nine teams cook in three groups of three for select groups in the community.
The diners vote for their favourite team, who get immunity from elimination, and the judges choose the worst-performing cooking duo to go to the first sudden-death cook-off.
The remaining non-safe teams head to Kitchen HQ where they cook off in a showdown to determine the second team in the elimination showdown.
