The other original four images images, taken by celebrity photographer Matt Holyoak, show Prince William and Kate posing with their three children - Louis, Princess Charlotte, 3, and Prince George, 4 - as well as with their wider family.
He was asked by William and Kate to take some private shots for their personal family album, in addition to the "historic" formal portraits captured by official photographer Mr Holyoak.
Louis was wearing a replica of the royal christening robe, made of fine Honiton lace lined with white satin, which was created in 1841 for Queen Victoria's eldest daughter, Victoria, the Princess Royal.
Bolton: Indictment of Russian Hackers Bolsters Trump's Hand Ahead of Putin Summit
Bolton was scheduled to appear on CNN's " State of the Union " Sunday, but was pulled by White House officials on Saturday. Bolton said that would be impossible since the United States has no extradition treaty with Russian Federation .
But because Will and Kate know what the masses want and Louis is the gift that keeps on giving, the royal couple gave us yet another reason to love them.
Taking her older sister duties very seriously, it's evident that Princess Charlotte is clearly besotted with her little brother. Uncle Harry and Aunty Meghan also join the family for this photo.
Fifth in line to the British throne, Prince Louis was born on April 23.
The Cambridges photographed for the first time as a family of five!
Princess Charlotte nearly stole the show - again - by affectionately holding her baby brother's hand during the shoot.