We take a look back at Matt Smith's time as the Time Lord, as the actor announces he's leaving the show at the end of 2013.
Matt Smith replaced David Tennant to become the 11th Doctor in the show's history. He's youngest actor to play the role - he was 26 years old when his casting was announced in 2009.
Matt will appear in the Doctor Who 50th anniversary celebratory episode, due on TV in November, before his "spectacular exit" in this year's Christmas special.
During his four years as the Doctor, Matt has fought baddies such as the Cybermen, Weeping Angels and - of course - the Daleks!
Believe it or not, Matt nearly didn't become an actor. When he was younger, he was on track to become a footballer. As he a teenager he played for Leicester City and Nottingham Forest - until a back injury forced him out of the game.
Matt's Doctor shares a laugh with his former sidekicks Amy Pond (played by Karen Gillan) and Rory Williams (Arthur Darvill) in New York.
Here's Matt with his latest companion Clara Oswald (played by Jenna-Louise Coleman) in the 2012 Christmas special The Snowmen.
Some fans will remember Matt for eating the unusual combo of fish fingers and custard! It happened in the series five opener when the Doctor met a young Amy Pond.
Yes, you've got hands! Here's Matt after regenerating as the Time Lord. He made his first appearance on New Year's Day 2010 in The End of Time Part Two.
Matt has made bow ties and tweed jackets cool - and in 2011 he became the first actor to be nominated for a Bafta award for playing the Doctor!