Royal baby Archie: Prince George let the name slip months ago - report

Prince Harry and Meghan Markle on Thursday (NZ time) announced their new baby boy is named Archie Harrison Mountbatten-Windsor.

However, it's since been revealed the name may have been let slip months ago by one of the youngest members of the Royal Family.

Archie is a shortened version of Archibald, composed of the German words "erchan"- meaning genuine or precious - and "bald" - meaning bold. The German link is speculated to be a nod to the baby's Windsor heritage.

And while the name was released on Thursday morning (NZT), it may have already been revealed by William and Kate's eldest son, and Archie's cousin, Prince George.

According to a witness, the boy let it slip while he was on a walk with his gran months ago, The Sun reports.

Prince George stopped to pat a man's dog, when he started talking to the future king.

"I asked George what his name was, even though I obviously knew it," the anonymous source told The Sun.

"To my astonishment he said 'I'm called Archie' with a big smile on his face.

"I don't know why he calls himself Archie, but kids often play with their names, and I think it's lovely."

The first photos of Archie were released on Thursday morning (NZ time).

He was born on Tuesday (NZ time), making him two-days-old when he was revealed to the world.

Photos posted to the Duke and Duchess of Sussex's Instagram account show the proud parents introducing him to Queen Elizabeth and her husband Prince Philip.