In 2007 a spin-off from Doctor Who started on CBBC called the Sarah Jane Adventures.
In the series, one of the Doctor's old assistants from the 1970s, Sarah Jane Smith, returns to battle baddies on Earth, assisted by a trio of pals - Rani, Luke and Clyde.
She also gets some help from a super computer called Mr Smith.
Sarah Jane has been seen recently in Doctor Who, when she appeared in an episode called School Reunion.