Prince George looked smart in his uniform as he walked nervously into school on his first day - without his mother, the Duchess of Cambridge, by his side.
Kate had hoped to join the Duke of Cambridge on the school run but is suffering from severe morning sickness and was too ill to attend, Kensington Palace said.
The four-year-old prince was helped out of the car by William after being driven through the gates of Thomas's Battersea, a fee-paying independent school in south London.
The prince will be known as George Cambridge to his classmates, the palace said.
George looked tentative, clutching his father's hand, as he was led towards the entrance of the school after arriving at around 8.45am.
The young prince shook hands with Helen Haslem, head of the lower school, as the Duke held his school bag ready for his first day.
Then, with William holding one hand and Ms Haslem the other, he walked inside.