Royal baby: Aerial video of Palace and BT Tower message
Aerial footage showed crowds outside Buckingham Palace following the announcement that the Duchess of Cambridge had given birth to a girl.
Video from high above London also captured a message announcing the news on the BT Tower.
The princess, who is fourth in line to the throne, was "safely delivered" at 08:34 BST, the palace said in a statement.
The Duke of Cambridge was present for the birth of the baby, who weighed 8lbs 3oz (3.7kg).