“She often jokes that he’s the only one of her kids who actually looks like her!” the source added.
"Sharing a sneak peek of Prince Louis’s handiwork ahead of his second birthday!” Kate captioned the candid snaps.
Among the cute photos was one that shows the cheeky little prince grinning for the camera while wearing a smart blue gingham shirt.
A follow-up pic shows the prince giggling while showing off his rainbow-coloured hands, while another snap shows Louis' brightly painted handiwork.
In a separate Instagram post, which appeared shortly afterwards, Kate shared several more snaps of the young prince playing arts and crafts.
"Instagram vs Reality," Kate captioned the two additional photos of the birthday boy.
Louis and his siblings, Prince George, six, and Princess Charlotte, four, are currently isolating at their country home, Anmer Hall, in Norfolk.
The royal update comes after the Cambridge trio recently showed their appreciation for British healthcare workers by taking part in a nationwide “clapping” initiative.