The British Prime Minister says it's "wonderful news" that the Duchess of Cambridge has given birth to a boy.
He was born at 4-24 this afternoon at St Mary's Hospital in London and weighed 8 pounds 6 ounces.
Mother and baby are both doing well, according to the official announcement outside Buckingham Palace.
David Cameron says a proud country is celebrating.
The Duke of Cambridge issued a brief statement tonight saying: "We could not be happier."
Meanwhile, in a statement from the US President and Mrs. Obama Congratulating Their Royal Highnesses The Duke and Duchess of Cambridge. President Obama said "Michelle and I are so pleased to congratulate The Duke and Duchess of Cambridge on the joyous occasion of the birth of their first child. We wish them all the happiness and blessings parenthood brings. The child enters the world at a time of promise and opportunity for our two nations. Given the special relationship between us, the American people are pleased to join with the people of the United Kingdom as they celebrate the birth of the young prince".