Before taking over the series as showrunner in 2010, the writer became known for penning some of the scariest episodes in the revival's run, and introducing iconic characters such as Captain Jack Harkness and River Song.
So, as fans prepare to tune into what could be Moffat's most dramatic episode yet, MailOnline takes a look-back at some of his most iconic tales in the Who-niverse. Steven's first story for New Who came during the first series 19 years ago, when Christopher Eccleston took the reins as the Ninth Doctor.
Played by John Barrowman, the immortal rogue took centre stage in the spin-off Torchwood, and returned to Doctor Who several times throughout its run. The Doctor comes dangerously close to falling for Reinette , after travelling through a time window on the spaceship using a fireplace. Considered a 'Doctor-lite' episode, Moffat delivered one of the show's scariest ever efforts, and another considered one of the best to ever hit screens
The one-off episode focuses on the sinister Weeping Angels, who only move when they're not being seen... or when you blink, inspiring the episode's title. In his final two-part story under Russell's stint as showrunner, Moffat set the stage for one of his biggest mysteries, the origin of River Song . While she meets her maker at the end of the episode, Moffat leaves viewers with plenty of questions about her origins, which would be answered in later series.
Considered another classic of the modern era, a post-regeneration Doctor is faced with the threat of escaped alien Prisoner Zero, with the Atraxi threatening to destroy Earth if he goes uncaptured. The mystery surrounding The Doctor's death came to a dramatic conclusion in the sixth series finale, also drawing an end to the long-running saga surrounding River Song's heritage.
The Angels Take Manhattan Marking the return of The Weeping Angels, viewers were left in floods of tears when The Doctor bid goodbye to his beloved companion Amy, and her husband Rory A devastated Doctor receives one last farewell from his friends in the form of a carefully placed afterword in a book, young Amelia's dreams of aventure come to a heartbreaking end in the moving episode.