Kate Middleton brought a little princess into the world at the Lindo Wing with Prince William by her side at 8.34am.
An announcement issued by Kensington Palace via email and Twitter said: “Her royal Highness The Duchess of Cambridge was safely delivered of a daughter at 8.34am.
“The baby weights 8lb 3oz. The Duke of Cambridge was present for the birth.
“The Queen, The Duke of Edinburgh, The Prince of Wales & The Duchess of Cornwall, Prince Harry & members of both families have been informed.
“Her Royal Highness and her child are both doing well.”
The baby is fourth in line to the throne, knocking uncle Prince Harry down to fifth place, and because of new laws she will keep her place in the line of succession even if she has a younger brother.
Just like Harry, she will also grow up with the “spare” to the heir tag and be pushed down the line of succession when George grows up and has children.
A girl had been hotly tipped by the bookies throughout the pregnancy with thousands placed on William and Kate having a daughter.
Now the hot betting topic will be what her name will be with Alice, Victoria, Elizabeth and Alexandra as the top choices.
Millions of people across the world are now waiting to see the princess as doctors, led by royal obstetrician Guy Thorpe-Beeston, run routine checks on mother and daughter.