Last season's Secret Circle should have been a hit. It was based on source material from the same author who wrote The Vampire Diaries, and had much of the same crew working on it. It failed miserably, and one of the reasons certainly has to do with the abysmal cast.
The one beacon of light in an otherwise dim cast was Phoebe Tonkin, the Aussie actress who played the good-hearted but often-bitchy witch Faye. Obviously she shone bright enough to be scooped up by her sister show, The Vampire Diaries.
Tonkin will play Hayley in a multi-episode arc beginning in the third episode of season four. Hayley is described as a wild, sexy and very free-spirited friend with whom Tyler shares a past. Undoubtedly, Tonkin will be there to create a love triangle between Tyler and Caroline.
Source: TV Guide