In the photos, Louis is seen smiling playfully as he enjoyed some finger-painting.
The royal tot looks delighted, showing off his hands smeared in rainbow-coloured paint.
Keen photographer Kate took the photos which were shared to the Royal Family's Instagram and Twitter page.
The post read: 'Happy Birthday to Prince Louis who is celebrating his second birthday today.
'Prince Louis is The Queen’s seventh great-grandchild.
'These 📸s were taken by The Duchess of Cambridge earlier this month.'
But Louis, the Duke and Duchess of Cambridge's third child, is actually the Queen's six great-grandchild.
Lena Tindall, the daughter of Zara and Mike, is the seventh great-grandchild, having been born two months after Louis.
The following year, Prince Harry and Meghan gave birth to Archie, becoming HRH's eighth great-grandchild.
Delighted fans flocked to social media to wish little Louis a happy birthday.