Simon Dorante-Day has made worldwide headlines as he claims to be the secret Australian son of Prince Charles and Camilla.

He was initially dismissed but after showing decades worth of research and evidence, he has got the world on his side.

"All roads lead back to Charles and Camilla," he says.

He's recently come under fire for the amount of research he's shared with the public.

“I’ve always been very open to doing interviews and sharing my story because at the end of the day, I want Charles and Camilla to submit to a DNA test and I believe that making my plight public will help me achieve that,” he told 7NEWS.com.au.

“And I understand that it’s easy to hear my story and think that I’m crazy and making it all up. But I say today what I’ve said all along - everything I’m claiming it checkable. Everything I’m claiming has been found through public records and reputable sources.

“Anyone who wants to report my story can go through the same checks and balances as I have. They just need to take the time to do so.

“I am a sane and intelligent man, a father and grandfather. I volunteer for the community and worked for many years as an engineer. I know my story is unbelievable, but if you don’t believe it - just check it.”

For those who want him to get a DNA test so he fades into the shadows, he's glad you're on board with what he wants.

“It always amuses me when people ask me this, because this is obviously what I’ve been working very hard to try and achieve,” he told 7NEWS.com.au.

“I’ve spent three years in the courts in an effort to have Charles and Camilla submit to a DNA testing. In Australia, Family Court proceedings cannot be reported on in the media which is why my actions haven’t been publicised.

“But this is a lengthy legal process and one I’m not giving up. I have taken my case to the Australian High Court, but they referred it back to the Family Court - and that will happen again in the next few months.

“I’m also seeking legal representation in the UK to take my fight abroad as well.

“I’m not interested in doing DNA tests with other distant royals because at the end of the day, I will still need to take it to court. I want this done the right way, before a judge.”

He's also been slammed by critics for the "family resemblance" photos he's been sharing on his Facebook page.

“They believe that this is the crux of my whole argument and think I don’t have any other research to back up my claims,” he said.

“But they couldn’t be further from the facts. Ever since my grandmother told me that Charles and Camilla were my parents, I’ve gone on a very careful path to discover the truth.

“I never just said, ‘Oh she said it so it must be true.’ Absolutely not. I went and did my own investigation, spoke to historians and went through records. And every road leads me back to Charles and Camilla."