The real reason behind Prince Harry's grumpy photos has finally been revealed.

Ahead of Harry's 40th birthday, royal expert has explained why the Duke of Sussex often appears grumpy in photographs.

According to the Express report, in an interview on The Sun, Ingrid Seward suggested that Harry’s serious expressions are not a sign of unhappiness but are linked to his dislike of being photographed.

"I don't think it's very plausible (that he'll get elements of his past life back). I really, truly believe Harry is happy," she said, adding, "He doesn't look happy in photographs because he hates being photographed, and of course we know he's got a war with all of us media."

"So when he hears the click of the camera, he puts on that grumpy look whereas Meghan's got the perma smile," Ingrid stated.

Despite his serious demeanor in public, Ingrid believes Harry is content with his life. She said, "I do think Harry is happy and I don't think for one moment that he wants to come back here (to the UK). I think he wants to be able to visit but that depends on the security and that's another story. He's always been obsessed about the security."