Meanwhile, her brother was too shy to greet the crowd.
You probably saw Princess Charlotte reach peak cuteness with her wave to the world's cameras - but you might have missed the adorable moment she shared with her older brother just afterwards.
We had a day less to wait for Princess Charlotte; she was born on 2nd May, with her name being announced on May 4th.
Wearing a pale dress and buckled shoes with white ankle socks, she turned around as she walked up the steps and offered a gorgeous royal wave.
After Kate had given birth to the new prince, William left the hospital to go home to Kensington Palace and pick up Charlotte and Prince George, who was still in his school uniform for the first meeting. Her mother bought the clothes from the children's boutique in the Spanish northern city of San Sebastian.
Her Majesty The Queen was the first to be notified of the birth.
It looks like Charlotte is totally owning her place in line for the throne. The young royals stayed at the hospital for just a few moments before returning to Kensington Palace.
As royal fanatics examined every frame of the footage carefully, they noticed that once they two children pass through the door with their father, 4-year-old Prince George seemed to put his arm around 2-year-old Princess Charlotte's shoulders.
Previously younger males would take precedence over older female siblings.