People only just spotting key detail in Harry and Meghan’s photo of their kids that you probably missed

Royal fans have noticed one thing about Meghan and Harry's children that they get from Princess Diana after the couple released their annual Christmas card last month.

The couple's Christmas card caused quite the stir, with people picking out all sorts of details and slamming the couple for certain choices.

However, there is a small detail that fans have only just picked up on, and it's pretty heartwarming.

One of the pictures on the card features a rare snap of the family-of-four all together.

And despite not being able to see the children's faces, there is one thing they have in common that is particularly striking.

The Christmas card caused some controversy. (Archewell)

Eagle-eyed fans noticed that both children - Archie and Lilibet - have taken after their father for their hair colour.

But Harry also inherited his hair colour from his mother Princess Diana, who had red hair when she was a little girl.

It seems as though the Spencer gene is pretty strong!

Despite opting for much blonder highlights in her adult years, Diana had very similar curls to Lilibet when she was the same age.

Taking to social media, one fan wrote: "Meghan is outnumbered by her ginger children and her ginger husband! Princess Diana's genes don't play!"

Another said: "Prince Harry and his family are looking more like Spencer's every time we see them.

"Princess Diana really said, a loyal son deserves to carry my genes and she hasn't missed a step."

The children's ginger locks can be seen in the picture. (Archewell)

A third added: "I cannot get over how beautiful Prince Archie & Princess Lilibet are & look at those Spencer ginger genes!! Oh my word!

"Their Granny Princess Diana would have been over the moon seeing them & probably is watching over them!"

Harry has noted himself in previous interviews just how like his mother Lilibet is.

In their Netflix series, he said: "I think at the moment I see a lot of my wife in Archie and a lot of my mum in Lilibet.

"She's very Spencer-like. She has the same blue eyes and sort of like a golden, red-ish hair."

In an appearance on The Late Show with Stephen Colbert, Harry even joked that he never thought his ginger gene would out-weigh Meghan's traits.

He added: "I actually really genuinely thought at the beginning of my relationship that, should this go the distance and we have kids, that there's no way the ginger gene will stand up to my wife's genes…But, I was wrong."