Steven Moffat's 10 Greatest Additions To Doctor Who
4. River Song
Spoilers, Sweetie! Though she and her Husband never meet in the right order, The Doctor's wife, River Song, is far more than the subject of a tragic love story.
The mystery of River's identity, and the nature of her relationship with The Doctor, was one of the greatest in Doctor Who's history. It carried the show through the better part of two series, culminating in a breathtaking reveal at the end of 'A Good Man Goes To War'.
Unlike some sci-fi love interests thrown in as a simple plot device, River can easily stand apart from The Doctor as an iconic character in her own right. Thanks in large part to actress Alex Kingston, River Song is now one of the most loved sci-fi heroines of all-time.