Alexander Armstrong (born in Rothbury, Northumberland, England, UK, 14 August 1970) voiced Mr Smith in The Sarah Jane Adventures and Sarah Jane's Alien Files, as well as the Doctor Who episodes The Stolen Earth and Journey's End. He appeared in Doctor Who again as Reg Arwell in The Doctor, the Widow and the Wardrobe.
In addition to acting Armstrong is a well-known comic and presenter. He headlines The Armstrong & Miller Show with his longtime comedy partner Ben Miller. In 2009, Armstrong and Miller's work on The Armstrong & Miller Show won them a BAFTA for "Best Comedy Programme." He is the presenter of BBC1 gameshow Pointless.