The sweet snap showed the Royal Family in a rare candid moment, laughing together as they posed.
What many royal fans noticed, however, was Prince Louis' striking resemblance to his mother the Duchess of Cambridge.
The adorable family photoshoot comes after news Prince William and Kate might consider expanding their Cambridge brood, with bookies placing bets on whether the couple will make an announcement before the year ends.
Betting site Ladbrokes have odds of just 7/2 for Prince William and Kate Middleton revealing they are expecting their fourth child by the end of the year.
Alex Apati of Ladbrokes said: "Baby mania is in full swing in the Royal Family right now so it's no surprise to see odds on a fourth Will and Kate baby so short."
Earlier in the year, Kate’s former school friend Jessica Hay exclusively told New Idea how she makes motherhood look easy.
"They’re a family of five now, so I would expect them to have one more baby to make a nice round number of six before long," Jess said.
"In fact, William’s telling everyone that they would love to have one more baby in the next 18 months!"