Doctor Who: 11 Most Memorable Companion Exits Of The Last Decade

6. River Song (Forest Of The Dead)

Back in 2008 the Tenth Doctor was introduced to someone who would go on to become one of the most important figures in his life. At the time, though, he was just as confused as the rest of us to come face to face with a stranger who seemingly knew everything about him - including his name. He subsequently spent the rest of Series 4's acclaimed Library two-parter trying to work out who the hell she even was (join the club, Doctor!) and by the end of the story things went from bad to worse when she sacrificed herself to save his life. Fans now know (though don't necessarily completely understand) the story of River Song which makes her death scene particularly more gut-wrenching in retrospect. It was sad at the time thanks to David Tennant and Alex Kingston's heartbreaking performances but the added knowledge of the history behind River's timey-wimey relationship with the Doctor makes the whole thing even more difficult to bear. This memorable departure was the end of River Song's journey - excluding her appearance in The Name of the Doctor - but for the titular Time Lord (and us), it was only just beginning.