Viewers slammed Kyle, Channel Nine and journalist Karl Stefanovic for the joke on social media.
"Stayed up to watch this and it was all just one big f***ing joke," one fan commented on Kyle and Jackie O's official Instagram account.
"Is this the best of Sunday night TV? Hopeless. Pure unadulterated s***e. @60Mins Karl and Kyle," another wrote on Twitter.
Media commentators also weighed in with journalist Peter Ford tweeting: "One thing for @kyleandjackieo to pull a prank about a life threatening illness. That’s on brand. Different thing for @60Mins to use it in a promo knowing they wouldn’t be delivering. That’s off brand."
"Anybody who has ever been diagnosed with terminal cancer, and had to tell loved ones, would not appreciate Kyle Sandiland’s ‘joke’ tonight," media personality and senator Derren Hynch also shared on social media.
However in a poignant video, Kyle addressed the backlash on his radio show and confessed that he had indeed been struggling with his mental health.
"Inside I'm very sad," he told Jackie on-air when he referred to how easily he welled up on the Channel Nine show.
"When you said 'I'm very worried about him,' a wave of emotion went through me and then I realised 'S*** I'm losing control here,' so I had to make up something as a joke," he explained.
"There is a great sadness in me that follows me around every day."
Kyle's co-host Jackie also spoke in the special about her 20-year professional relationship and how his divisive behaviour is "the hardest part" about working with him.
"He has this really beautiful side and then with that comes this other side that you think 'Why did you have to say that?'"
"I'm not his mother, it isn't always my responsibility to pull Kyle up. I mean, he's a big boy," she added.
The pair have been renowned for their on-air pranks, however Jackie admitted that their shock tactics have softened over the years.
“There were things we did that were terrible I think and if those things hadn’t have happened and if people hadn’t have shown a light on it, would we have just kept going with it," she told Karl Stefanovic.
"Trying to stay number one is harder than getting to number one because you’re there and then you think, ‘Ok, what else should we do? We’ve already done this shocking segment. How can we do another shocking … Something even more shocking’.
“I think that’s where our thought process was back then and thank God we’ve learned from that and we don’t do that sort of stuff anymore.”