Listeners of the KIIS 106.5 breakfast show will be aware of the shock jock's hate for Campbell, however, he has never fully explained why.
Speaking to news.com.au, the radio star claimed he used to consider Campbell a "mate" until he "jumped on the bandwagon" and turned on the radio host.
"That c**k breath, I can't stand him," Sandilands said when asked about the television host.
"David Campbell I've known for a long time. Good guy, nice guy. I wasn't hanging out of his pocked but I'd seen him and bring him onto our show all the time," he continued.
Even when Campbell joined rival radio station Nova, Sandilands said that he continued to support the fellow entertainer's career.
"He brought a song out and our station wasn’t going to play it and I said, ‘I don’t think that’s fair.' Just because he’s on another station doesn’t mean we should ban him. I just think the right thing to do is just play it."
"I thought I’d stretched the friendship for him, you know, even though he was on an opposition network."
But Sandilands told news.com.au the friendship soured when Campbell criticised him in the media.
"As soon as he had a chance to have a little whinge during one of my many f**k-ups of life, he was one of the ones to first sink the boot in as many people did," the radio host said.
"And I thought, f**k you dog! I’ve done the right thing by you the whole time and he just jumped on the bandwagon. He’s just a peasant. Now he’s no friend of mine."
Sandilands and Campbell haven't had to work together in many years, and haven't even spoken in several years, but the KIIS FM host says he has come face-to-face with the Channel Nine host a few times.
"If that little slender David Campbell walks in, in his Roger David suit and sees me, he just does a little pirouette and out the door," Sandilands claimed.
This article originally appeared on New Idea.