Man claiming to be secret son of King Charles and Queen Camilla says there’s only ‘one way’ to get the truth

Simon Charles Dorante-Day is adamant that he is related to the Royal Family believes there's only 'one way' to get to the truth.

The 58-year-old Australian man has gone viral on several occasions over the last decade after claiming he is the love child of King Charles and Queen Camilla.

Simon, born back in 1966 to parents living in England, was put up for adoption and taken to Australia to be raised by a loving family.

However, one of his adoptive grandparents - who was reported to have been a former household employee of the late Queen Elizabeth II - lifted the lid of his supposed Royal heritage, telling him that he was closely related to Charles and Camilla.

The current King would have been around 17 years old when Simon was born, and Camilla, 18.

King Charles and Queen Camilla have been married since April 2005 (Anwar Hussein/Getty Images)

Now Simon has claimed there is only 'one way' to get to the truth - a four-way paternity test.

This is a DNA test that analyses samples from a child, the mother, and two potential fathers.

After sharing 'comparison' pictures of himself beside Prince William, Prince Harry and King Charles on Facebook, Simon believes that he looks more like Charles than his two sons - which, he says, 'raises the obvious question' of 'who are Charles' real sons?'

"My wife, Dr. Elvianna, and I believe a 4-way Paternity test is the only way to resolve this issue once and for all," he wrote on Facebook on 7 September.

"The truth of the game that has been played by the Monarchy, the Government, and the Establishment for 58 years needs to be exposed. The lies and corruption must be uncovered for what they are, criminal activity.

"It's not just what happened to me as a child, and what I remember from growing up in England, but it's also what's happened since to myself, my wife, and my children that supports our argument."

Simon believes believes there's only 'one way' to get to the truth (Facebook/PrinceSimonCharles)

Simon believes that the silence the British institution have kept on the matter ever since he came forward tells him all he needs to know.

Speaking with 7NEWS.com.au, Simon noted: "It's worth me pointing out that Charles and Camilla, Buckingham Palace, the entire royal family - not one of them has ever said my claims are not true.

"They've never denied what I believe, told me I'm wrong. And I think their silence speaks volumes."

Tyla has contacted Buckingham Palace for comment.