Gethin Jones (in-universe)

Gethin Jones (born 12nd February 1978) has been a presenter for Blue Peter since 2005. In 2009 Maria Jackson watched an episode with him on it. (SJA: Invasion of the Bane)

In Doctor Who
Gethin Jones played a Cyberman in Rise of the Cybermen and The Age of Steel. This makes him the first person to play both himself and a character in Doctor Who.