LONDON -- After a big year for the royal family, Wednesday is all about the Duchess of Cambridge, better known as Kate Middleton. She's turning 37!
From graduations to engagements, weddings and pregnancies, we've watched Prince William and Duchess Kate grow up and start their family before our very eyes.
Now they're a family of five. Last April the couple welcomed their third child, Prince Louis. The little one is fifth in line to the throne, behind big siblings Prince George and Princess Charlotte.
In the video above, take a look back at their major family milestones.
PHOTOS: Will & Kate through the years
MORE ROYAL FAMILY COVERAGE
Prince William, Prince Harry share families' Christmas cards
The British royal family tree and the line to the throne
A look back at the wedding of Prince William, Kate Middleton
Happy Birthday, Duchess Kate! See photos of the royal family through the years