Doctors with pony companions: 3  
In an attempt to escape their banishment to Earth, the Doctor tried to bypass the TARDIS dimensional lock. This resulted in their sudden arrival in Equestria. Princess Celestia was able to put them into the Gaean Unified Intelligence, Defense, and Espionage agency, under the command of the long-suffering Captain Drawbridge Steward. Also pictured are Fleur de Lis, the cunning ex-assassin; Fancy Pants, the frazzled junior whip charged with reporting back to Parliament; and Cadence, the sympathetic princess-to-be.  
Not pictured: the Master, who has followed the Doctor over in an attempt to get that cursed do-gooder to notice him.