Ex-Top of the Pops presenter Reggie Yates is the latest star to sign up for a part in Doctor Who.
The 23-year-old will appear as the brother of the Doctor's new assistant Martha Jones, played by Freema Agyeman.
Doctor Who boss and writer Russell T Davies has also been talking about a future episode where the Doctor meets the famous writer William Shakespeare.
He described the show, which uses loads of special effects, as "one of our most ambitious projects to date."
Russell T Davies said: "Viewers can look forward to Shakespeare giving the performance of his life in order to save the earth from destruction."
Other new cast members to join the show include Trevor Laird as Martha's dad Clive and Adjoa Andoh as her mum Francine.
Reggie has already finished filming his first episode of the show which will be broadcast in 2007.