Filming has begun in Cardiff on the fourth series of 'Doctor Who', with David Tennant joined by new co-star Catherine Tate.
Tate will play The Doctor's new assistant, Donna Noble, who also appeared in last year's 'Doctor Who Christmas Special'.
Commenting, Tate said: "I am delighted to be returning to Doctor Who. I had a blast last Christmas and look forward to travelling again through time and space with that nice man from Gallifrey."
Freema Agyeman, who played The Doctor's assistant Martha Jones in season three, returns to the show in the middle of the fourth series.
The new series of 'Doctor Who' will premiere on BBC One next spring.
