The project is based on the Secret Circle novels by L. J. Smith, who also wrote the Vampire Diaries books.
The show focuses on a young girl who moves to Salem and discovers that she is a witch.
Deadline says that Williamson has now signed up to work on the script and executive produce the project. His Vampire Diaries colleague Julie Plec is not currently attached to the show but could join later.
The CW has not yet ordered a pilot of the programme but it is said to be a strong contender. So far this year, the network has asked for episodes of Danni Lowinski, Hart Of Dixie, Heavenly, Cooper & Stone and Awakening.