Kent (The Wedding of River Song)

Doctor Kent worked for the organisation run by Amy Pond in an alternate timeline. The organisation was dedicated to saving the Eleventh Doctor from dying. Kent monitored the passage of time in the King's Chamber of the Great Pyramid of Giza until the Silents activated her Eye Drive and killed her. (TV: The Wedding of River Song)

Behind the scenes
The actor Emma Campbell-Jones also portrayed Cass, a gunship pilot, in the mini-episode The Night of The Doctor.