Former Top Of The Pops presenter Reggie Yates will play a leading role in the new series of Doctor Who.
Yates was a joint host on the final episode of Top Of The Pops
BBC Radio 1 DJ Yates, 23, will star as the brother of the Time Lord's new assistant, medical student Martha Jones - played by Freema Agyeman.
Actor Dean Lennox Kelly, best known as Kev in hit C4 drama Shameless, will guest star as William Shakespeare.
The episode features Shakespeare giving "the performance of his life" to save the Earth, said Russell T Davies.
Dean Lennox Kelly recently appeared in BBC drama Sorted
"The Shakespeare episode is, without doubt, one of our most ambitious projects to date," said Davies, who is executive producer of the series and the show's main writer.
Other new faces in the series include Trevor Laird, who plays Martha's father, and Adjoa Andoh, as her mother.
The new series - which will be the third since the cult programme was revived, and the second featuring David Tennant in the title role - is scheduled to air in 2007.
Billie Piper announced her departure from the show as assistant Rose Tyler in June this year.