'Come clean': Aussie man convinced he's Prince Charles and Camilla's secret son urges them to speak out

An Australian grandfather convinced he's the secret love child of Prince Charles and Camilla Parker Bowles has urged the royals to "come clean" about their past. 

Appearing for an interview on Sunrise, 55-year-old Simon Dorante-Day insisted he would be returning to court to continue his decades-long battle to prove Charles and Camilla are his biological parents, and that he was adopted out to the family of a former member of Queen Elizabeth's staff when he was still a baby. 

"The evidence speaks for itself, the face is what gives it away," Dorante-Day said, referencing a recent Facebook post of his that claimed to show a family resemblance between his son Liam and the Queen. 

Dorante-Day's regularly shares updates and what he claims are various pieces of evidence and photographic proof of his royal linage on his Facebook page, which has gained some 9000 followers. 

"People seem to think I’m getting a big name and money out of this, I'm not getting anything out of this, this is costing me to do this," he told Sunrise. 

"We're forced to do this because we're tired of moving around Australia hiding this secret that’s not our secret." 

Dorante-Day claimed his birth certificate is "complete rubbish", and that it would be included in the portfolio of evidence he intended to take to court. 

"It's just unfair that I constantly have to fight this when really they know the truth," he said. 

"The longer this thing runs, the more they're going to have egg on their face, not me." 

Among Dorante-Day's recent social media posts are several tributes to Prince Philip, who died earlier this month. He wrote that his alleged "grandad's" DNA would "live on" in him and his children. 

"His fingerprints are all over my life and whilst some of that might appear to be harsh or hard it made me the man I am," he wrote.