Princess Kate looks beautiful in a pair of high-waisted skinny jeans and a crisp blouse from M.i.h Jeans.
The caption said "Happy Mother's Day from our family to yours," and royal followers commented with excitement.
Princess Kate has been praised for her model parenting and down-to-earth approach to motherhood.
Princess Kate gently handled four-year-old Prince Louis' mischievous antics at Queen Elizabeth II's Diamond Jubilee Celebrations.
The Prince and Princess of Wales continue to be impressive parenting role models to modern parents today.