Princess Diana reportedly had a sweet nickname for Prince Harry when he was still very young. And according to a royal expert, the unique nickname proved that the Princess of Wales actually favored Prince Harry to be the future king and not Prince William.

In the Channel 5 documentary “William & Harry: Princes At War?” royal correspondent Robert Jobson claimed that the late royal came up with Prince Harry’s nickname because if it was up to her, she would’ve urged the Duke of Sussex and not the Duke of Cambridge to be the future king of England.

“She used to refer to Harry as GKH (Good King Harry) because she thought he’d probably be better equipped for the role in the future than William,” he said.

This wasn’t the only time that Jobson talked about Princess Diana’s nickname for her youngest son. During last year’s episode on his podcast, Jobson spoke with the Princess of Wales’ former private secretary, Ken Wharfe. The latter revealed that he was also aware that his former boss gave Prince Harry the nickname “Good King Harry.”

Meanwhile, Princess Diana’s former royal butler, Paul Burrell, also talked about the royal siblings in the documentary. He said that Prince Charles’ ex-wife made it a point to not treat her sons differently even though their future roles in the monarchy couldn’t be more different from one another.

And even at a young age, Prince Harry also knew that Prince William was destined to be King. During one of their fights, the Duke of Cambridge said that he didn’t want to be King and Prince Harry immediately offered to take over the important position.

“His mother [Princess Diana] thought that was very amusing. She said that’s a good idea, Harry, you’d make a great king,” Burrell said.

Unfortunately, Princess Diana never had the chance to see the future of her sons. The royal passed away on Aug. 31, 1997, following a fatal car crash in Paris.

Princess Diana, Prince William, Prince Harry
Pictured: Princess Diana, Prince Harry, Prince William gather for the commemorations of VJ Day, 19 August 1995, in London. Getty Images/Johnny Eggitt/AFP