Doctor Who is to have a new companion when the drama returns - but there will still be room for his current co-star.
Actress Freema Agyeman is to play Martha Jones in three episodes of spin-off show Torchwood. She said it was a chance to 'expand' her character.
She will miss the first half of the fourth series of Doctor Who, but will then return to the BBC One programme.
The new companion will be revealed soon and will appear in the entire 13-week run, which begins filming this month.
