Royal fans claimed Princess Eugenie's son August is the double of Prince Harry's boy Archie.
Prince Andrew's youngest daughter yesterday posted an Instagram snap of her two-year-old stroking the head of newborn baby brother Ernest.
The 33-year-old mum - married to Jack Brooksbank, 37 - gave birth last week but managed to keep it secret until Monday's big reveal.
She captioned the photo: "Augie is loving being a big brother already."
However, her followers were distracted by the apparent similarities with the Duke of Sussex's eldest child, who turned four the same day as King Charles' Coronation last month.
Harry and Meghan have not released many official photos of their son, but their Christmas card shows them all, alongside daughter Lilibet.
In the Christmas card photo, Archie is looking side on, the same as August in the picture with Ernest.
And many believe their profiles are uncanny.
One wrote: "It's incredible how much Archie and August are similar! How cute are these two little cousins."
"August and Archie are twins," another added.
A third wrote: "In my family, the cousins all look alike too. Windsor genes are strong. August does look like Archie!"
Another commented: "Congratulations to Eugenie and Jack on the birth of her son Ernest. Is it just me or does the photo of Eugenie's son August look identical to the photo we have been getting shown of Archie?"
"Honestly, Eugenie could post a photo of Archie and say it's August, I wouldn't know the difference," another wrote.
"We've not seen much of either, and the little I've seen, I think they look similar."
Cousins Prince Harry and Princess Eugenie have always been close, and it is likely Archie and August will have met in person despite the Sussexes' move to the US.
Eugenie and Jack are reported to have visited Harry and Meghan at their California home multiple times.
Ernest was born at the private Portland Hospital in London, like his brother - and his mum before him.
Born last Tuesday weighing 7lbs 1oz, his name pays tribute to his late grandfather, Jack's dad George, who died aged 72 in 2021, and Eugenie's mum Sarah Ferguson's father Major Ronald Ferguson.
Eugenie also said his name was a tribute to his great great great grandfather George V, whose middle name was also Ernest.
The new arrival is 13th in line to the throne, pushing Prince Edward into 14th place.
Buckingham Palace said: "Princess Eugenie and Mr Jack Brooksbank are delighted to announce the safe arrival of their son, Ernest George Ronnie Brooksbank."
Ernest will not receive a title, however, and – according to rules laid down by George V in 1917 - is not entitled to be called His Royal Highness.
He is the first of Elizabeth II's great-grandchildren to be born since her death last September.
