Meghan Markle fans spot shocking detail in newly shared photo of Prince Archie on his birthday

Meghan Markle shared an adorable photo of Prince Archie to mark his sixth birthday.

But royal fans have noticed a surprising detail about the image, which was posted on Instagram on Tuesday (6 May).

In the image, Archie can be seen peering over the balcony, facing away from the camera.

The youngster appears to be looking towards the beautiful sunset in the background, with Meghan writing alongside the post: "Our son. Our sun.

"Happy 6th birthday to Archie!

"Thank you for all of the love, prayers, and warm wishes for our sweet boy. He’s six! Where did the time go?

"(And for all of you who came to celebrate with us at his party last weekend, thank you for making his birthday so incredibly special)."

After Meghan posted the image online, people were quick to comment, with many saying the same thing.

Plenty of fans commented on Archie's height, with one writing: "What a beautiful picture of Prince Archie, he is growing so tall. Happy birthday Archie."

While another said: "He’s getting so big and tall definitely takes after his papa, Prince Harry."

And a third added: "IMO Archie is either a very tall 6 year old or the rail is very low!!"

While Prince Harry is said to be around 6ft 1in, Meghan is reported to be 5ft 6in, so it would make sense that Archie could be on the taller side for his age.

Meghan Markle shared a photo of Archie to mark his sixth birthday (Instagram/@meghan)

Meghan - who is also mum to Lilibet, three - recently opened up about being a parent in her podcast, Confessions of a Female Founder.

In a recent episode with Bumble founder Whitney Wolfe Herd, she spoke about suffering from pre-eclampsia after the birth of one of her children.

Pre-eclampsia is a serious condition that can occur during birth or in the postpartum period. It is characterised by high blood pressure and protein in the urine.

"We both had very similar experiences - though we didn't know each other at the time - with postpartum, and we both had preeclampsia. Postpartum preeclampsia," Meghan said.

"It's so rare and so scary. And you're still trying to juggle all of these things, and the world doesn't know what's happening quietly. And in the quiet, you're still trying to show up for people - mostly for your children - but those things are huge medical scares."

Meghan with Archie and Lilibet (Instagram/@meghan)

In response, Whitney said she would 'never forget' the images of Meghan shortly after Archie's birth.

"I mean, I'll never forget the image of you after you delivered Archie, and the whole world was waiting for his debut," she noted.

"I was either just becoming or about to become a new mum, and I was like, 'Oh my God, how is this woman doing this? How is this woman putting on heels and going and debuting a child in this, you know, beautiful outfit in front of the entire world?'"