Princess Charlotte Gets Dropped Off on First Day of School

Huge day for Princess Charlotte ... it's her first day of school and her Royal parents couldn't look prouder.

Prince William and Kate Middleton sported huge grins Thursday as they arrived at London's exclusive Thomas's Battersea school. The Royal family walked hand in hand with 4-year-old Charlotte and Prince George. Charlotte -- who is fourth in line to the throne -- looked giddy but also a bit nervous meeting the headmaster.

This is 6-year-old George's third year at the school. You can tell he's already a pro at schooling ... giving the headmaster a firm handshake. William said Charlotte's very excited for her first day as they all walked in.

Thomas's Battersea is a pricey private school. Tuition at the school with 560 students (21 students in Charlotte's class) is around $7,900 for ages 4 to 13 per term. But, Charlotte's getting a sibling discount ... which lowers tuition by about 150 bucks per term.