Prince William and Prince Harry once shared a very close bond, but have been feuding for a while now, with royal experts dubbing it the classic clash between "the heir and the spare." It has now been revealed that Harry had become aware of his and his brother's distinctly different royal destiny at a very young age.

Ken Wharfe, former bodyguard of the royal siblings, recalled that the Duke of Sussex had made a shocking comment at the mere age of four which makes his recent royal exit not too surprising. The young royal made the remark when he and William were travelling from London to Gloucester with their mother Princess Diana for a weekend.

In Channel 5's new documentary "Prince Harry: The Troubled Prince," Wharfe recalled about the trip, "Diana would always take the two boys to Highgrove in Gloucestershire. On this particular occasion Diana was driving, I was sat in the front, William and Harry in the back. They'd clearly got off to a bad start because they were arguing before we'd even left."

Wharfe added that it seemed like the duo had been fighting like any normal siblings in the back seats of the car, with their nanny acting as the referee, before Harry dismayed them with his comment. "Harry out of nowhere said: 'William, one day you'll be king, I won't, it doesn't matter therefore I can do what I like,'" he recounted.

Wharfe said that Princess Diana was stunned by the remark and asked her younger son where he learned it from.

William, second in line to the British throne, is a direct heir after his father Prince Charles. The Duke of Cambridge will become the Prince of Wales after his father takes over the throne, and will eventually become the King. Meanwhile, Harry who was next in line after William at the time of his birth has been pushed down to the sixth position following the birth of William and Kate Middleton's children Prince George, 8, Princess Charlotte, 6, and Prince Louis, 3.

While William has started taking more royal responsibilities as his grandmother Queen Elizabeth II turned 95, Harry has quit his royal life with his wife Meghan Markle and established a lucrative career in the United States.

Princess Diana
11 September 1989: Princess Diana stands with Prince William and Prince Harry on the steps of Wetherby School on her youngest son's first day Tim Graham/Getty Images