Welcome to the world Prince George Alexander Louis of Cambridge!
Want to know more facts about the royal baby, including to whom he's related?
Learn more in our infographic below and in our Royal Family Tree:
One of the world's highest profile couples - William and Kate (the Duke and Duchess of Cambridge) - have announced that they are expecting a child.
Due to Britain's constitutional changes, the child will become an heir to the crown, regardless of gender. The baby will be third in line to the throne, after its grandfather (Prince Charles) and father, moving Prince Harry to fourth in line.
Already buzzing are possible names for the child.
The most common names used by the British Royal Family are George and John for boys and Elizabeth, Sophie and Victoria for girls. There's a copy of the British Royal Family Tree available on MyHeritage.
What do you think the newborn's name might be?
Although she came to the throne on this day in 1952, her coronation took place on June 2, 1953.
Queen Elizabeth II is the male-line great-granddaughter of Edward VII, who inherited the crown from his mother, Queen Victoria. His father, Victoria's consort, was Albert of Saxe-Coburg and Gotha.
Queen Elizabeth is a patrilineal descendant of Albert's family, the German House of Wettin. This princely house claims other notables, such as King Albert II of Belgium and former King Simeon II of Bulgaria.
Through Victoria - and several of her great-great-grandparents, Elizabeth is directly descended from many British royals: