But a few new side-by-side photos have us convinced that the Duke and Duchess of Cambridge's kids are actually carbon copies of each other.
William and his wife Kate Middleton are the parents of five-year-old George, three-year-old Charlotte, and nine-month-old Louis. Since his birth last April, we haven't seen a lot of little Louis other than photos from his christening, a family portrait to mark Prince Charles' birthday, and the family's annual Christmas card.
An Instagram fan account called @loveprincessdiana posted a side-by-side photo of Prince George and Prince Louis in December, and the resemblance between the two brothers is uncanny.
The photo shows Prince George's official Christmas picture in a courtyard at Kensington Palace in late Nov. 2014, and a crop of Prince Louis from the family's official Christmas card, taken in autumn 2018 at their country home Anmer Hall in Norfolk.
WATCH: Can Prince Louis already crawl? Story continues below video.
They even have the same smirk! Come on! They're also both rocking blue sweaters (a vest, in George's case) and white collars.
We're not worthy.
If you're not already at max cute for the day, the same account also posted a side-by-side pic that includes Princess Charlotte.
In the crop, from an official family photo taken at Kensington Palace in Oct. 2015, baby Charlotte has a similar smirk to her brothers and — be still our hearts — a pink cardigan over a ruffled white collar.
Kate loves dressing her kids in classic, traditional styles such as these. "If they wear very simple things ... it's timeless in that you can't really date a specific photo or put them in something that seems out of date," kids' wear designer Rachel Riley, who has dressed Prince George, told The Telegraph in 2017.
"They have chosen a very traditional look and are a traditional family," Riley said.
Their classic looks certainly stand out in the three original photos used in the side-by-sides.
So many wholesome sweaters...
All cardigans. All collars. All the time.
The knee socks! We're dead.