The tiny detail in Prince George's birthday portrait we all might have missed

A simple photograph revealed how 'regular' the Royal children are in real life.

As Prince George turned five, Royal tradition dictates a portrait of the young prince to be released to the public for the occasion. This picture was released by the Duke and Duchess of Cambridge on Sunday through Instagram.

Unlike most royal portraits, it was a casual picture, which saw the young Prince leaning back against a wall, glowing with laughter. Read more about the Royal family on our Twitter account @amomama_usa.

The future King was wearing a simple white short-sleeved shirt, with blue piping along the collar, buttons, and sleeves. The shirt was paired with navy blue shorts, the kind of which the Prince is usually seen wearing all year round.

Prince George was all-teeth for the photo, with his tiny hands tucked behind him. George's stance and posture seemed to be passable for the Royal portrait. It was taken after Prince Louis' christening earlier this month.

A deeper inspection of the picture revealed that the last button of the Prince's shirt, just above the shorts seems to have come undone.

In the past, such a photo, would not have been released to the public, as most royal pictures are subject to intense scrutiny from fans and followers all over the world.

The Royal family usually releases pictures after careful thought and internal inspection. The release of this picture suggested that the Royal children are held to a more relaxed standard as compared to the previous generation.

Prince William and Kate usually strive to give all their children a regular childhood within the constraints of the Royal family. All their children are consciously kept out of the limelight but this policy has recently been relaxed.

Prince George and Princess Charlotte have been making more public appearances, much to the delight of their fans from around the world.