Prince George, Princess Charlotte and Prince Louis will probably be very excited to have a new baby cousin.
Meghan Markle and Prince Harry's boy was born on Monday, but it doesn't seem like they've had a chance to meet little Archie yet.
But it turns out that George might already have a rather unusual connection to his new cousin - and it's all because of his name.
Earlier this year the little Prince baffled a dog walker by telling them his name was Archie when he was out with his sister and granny Carole Middleton.
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Speaking to The Sun , the woman said: "I was asked by a police minder not to take a photo of the children, which I didn’t, but George started stroking my dog.
"Just to be friendly I engaged in a bit of small talk and I asked George what his name was, even though obviously I knew it.
"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."
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He might have just come up with the name on the spot, or it might be a nickname he uses - so he might have to come up with another one now his little cousin is called Archie!
George already has several nicknames, and with his schoolpals reportedly calling him PG and Kate and Wills using Tips.
Meghan and Harry revealed their son's name by posting a lovely photo of him meeting great-granny the Queen for the first time on Wednesday afternoon.
