Filming of 2012's Doctor Who Christmas episode starts this week with two big film and television stars joining the show.
On joining the show, Richard says: "I played Doctor Who in the digital animated Scream Of The Shalka and I'm honoured to be in the Christmas Special."
Tom Ward, who has starred in BBC One's in Silent Witness as Harry Cunningham since 2002 also joins the Doctor, played by Matt Smith, and his new companion played by Jenna-Louise Coleman.
It is written by Steven Moffat and directed by Saul Metzstein. It will be shot in Cardiff at BBC Wales' studios.
Doctor Who is coming soon to BBC One and the Christmas Special will be followed by a further eight episodes next year.
Doctor Who is a BBC Cymru Wales Production for BBC One.