Author LJ Smith, whose best-selling Vampire Diaries novels were turned into a hit TV show, has died at the age of 66.

Lisa Jane Smith published the original four-book series, about a love triangle involving two vampire brothers and an orphaned young woman, in 1991 and 92, before releasing another Vampire Diaries trilogy in 2009-11.

However, she was dropped from her own book series and replaced by new authors by publishers, but Smith continued releasing new instalments unofficially as fan fiction.

The official books were adapted for TV in 2009 and the show became a teen favourite over its eight years.

Described by the Guardian as a "deliciously pulpy supernatural soap opera", the TV version was part of a craze for vampire stories that also included Buffy the Vampire Slayer, Twilight and True Blood.

The show won a total of 30 Teen Choice Awards including six consecutive prizes for best fantasy/sci-fi actress for Nina Dobrev, who played Elena for the first six seasons.

Dobrev starred alongside Paul Wesley and Ian Somerhalder as brothers Stefan and Damon Salvatore.

Smith had originally been hired to write the novel series by a book packager - who sold them to a publisher - under a deal where they, not she, owned the rights.

She said the packager dropped her in 2011 and handed over her unpublished eighth instalment to an anonymous ghostwriter, who went on to publish two further Vampire Diaries books.

The series was then handed on to an author using the pen name Aubrey Clark for three more. However, Smith's remained the most prominent name on the book covers as the series creator.

The author said the situation left her feeling "trashed" and "mutilated".

However, she went some way to reclaiming her creation when the Vampire Diaries was added to an Amazon Kindle scheme granting official permission for anyone to publish fan fiction linked to existing books.

Smith launched a new unofficial Vampire Diaries trilogy through that scheme, which picked up where her last official book left off.

She was also known for the Night World novels, which also feature vampires as well as witches, werewolves and shapeshifters, who secretly live among the human race.

Nine Night World volumes were published between 1996 and 98, before Smith took a decade-long break from writing. She said it was a result of writer's block while two family members dealt with cancer.

Smith's The Secret Circle trilogy, published in 1992, was also turned into a TV drama in 2011. She also wrote the Dark Visions and The Forbidden Game trilogies.

A statement on her website said: "Lisa was a kind and gentle soul, whose brilliance, creativity, resilience and empathy, illuminated the lives of her family, friends and fans alike.

"She will be remembered for her imaginative spirit, her pioneering role in supernatural fiction, and her generosity, warmth and heart, both on and off the page."