Brittany and Cynthia Daniel have paid tribute to the late Francine Pascal

They told People magazine in a statement: "She touched the hearts and minds of so many with her entertaining and relatable portrayals of teenage life.

"We always felt loved and appreciated by Francine. She'll be greatly missed."

The writer's book publisher are "proud" to have worked with Francine over the years.

A St Martin's Publishing Group spokesperson said: "St. Martin's is proud to have been a publisher of Francine Pascal's Sweet Valley High series whose iconic and beloved characters captivated generations of teens and adults."

Francine - who was also ex ecutive producer on the TV series, which ran from 1994 to 1998 - passed away from lymphoma at NewYork-Presbyterian Hospital in Manhattan at the age of 92, her daughter Laurie Wenk-Pascal confirmed to the New York Times newspaper.

The author wrote the first 12 'Sweet Valley High' books before handing the series over to a team of writers she oversaw, providing outlines and a "bible" of character descriptions for them to follow.

The series sold over 200 million copies and sparked several spin-offs, including 'Sweet Valley Twins', 'Sweet Valley Kids' and 'Sweet Valley University'.

She once told People magazine of 'Sweet Valley High': "Sweet Valley is the essence of high school. It's that moment before reality hits, when you really do believe in the romantic values - sacrifice, love, loyalty, friendship - before you get jaded and slip off into adulthood."

She also wrote several books for adults, including the non-fiction 'The Strange Case of Patty Hearst', a fictionalised memoir about her life with late second husband John Pascal titled 'If Wishes Were Horses', and horror novel 'Save Johanna!'.